LUCENE-7277: Make Query.hashCode and Query.equals abstract.

lucene/CHANGES.txt

@@ -136,6 +136,9 @@ Documentation
 
 Other
 
+* LUCENE-7277: Make Query.hashCode and Query.equals abstract. (Paul Elschot, 
+  Dawid Weiss)
+
 * LUCENE-7174: Upgrade randomizedtesting to 2.3.4. (Uwe Schindler, Dawid Weiss)
 
 * LUCENE-7205: Remove repeated nl.getLength() calls in

lucene/MIGRATE.txt

@@ -1,5 +1,10 @@
 # Apache Lucene Migration Guide
 
+## Query.hashCode and Query.equals are now abstract methods (LUCENE-7277)
+Any custom query subclasses should redeclare equivalence relationship according
+to the subclass's details. See code patterns used in existing core Lucene query
+classes for details.
+
 ## The way how number of document calculated is changed (LUCENE-6711)
 The number of documents (numDocs) is used to calculate term specificity (idf) and average document length (avdl).
 Prior to LUCENE-6711, collectionStats.maxDoc() was used for the statistics.

lucene/core/src/java/org/apache/lucene/search/BlendedTermQuery.java

@@ -224,20 +224,21 @@ public final class BlendedTermQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    BlendedTermQuery that = (BlendedTermQuery) obj;
-    return Arrays.equals(terms, that.terms)
-        && Arrays.equals(contexts, that.contexts)
-        && Arrays.equals(boosts, that.boosts)
-        && rewriteMethod.equals(that.rewriteMethod);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(BlendedTermQuery other) {
+    return Arrays.equals(terms, other.terms) && 
+           Arrays.equals(contexts, other.contexts) && 
+           Arrays.equals(boosts, other.boosts) && 
+           rewriteMethod.equals(other.rewriteMethod);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + Arrays.hashCode(terms);
     h = 31 * h + Arrays.hashCode(contexts);
     h = 31 * h + Arrays.hashCode(boosts);

lucene/core/src/java/org/apache/lucene/search/BooleanQuery.java

@@ -421,17 +421,18 @@ public class BooleanQuery extends Query implements Iterable<BooleanClause> {
    */
   @Override
   public boolean equals(Object o) {
-    if (super.equals(o) == false) {
-      return false;
-    }
-    BooleanQuery that = (BooleanQuery)o;
-    return this.getMinimumNumberShouldMatch() == that.getMinimumNumberShouldMatch()
-        && this.disableCoord == that.disableCoord
-        && clauseSets.equals(that.clauseSets);
+    return sameClassAs(o) &&
+           equalsTo(getClass().cast(o));
+  }
+
+  private boolean equalsTo(BooleanQuery other) {
+    return getMinimumNumberShouldMatch() == other.getMinimumNumberShouldMatch() && 
+           disableCoord == other.disableCoord &&
+           clauseSets.equals(other.clauseSets);
   }
 
   private int computeHashCode() {
-    int hashCode = 31 * super.hashCode() + Objects.hash(disableCoord, minimumNumberShouldMatch, clauseSets);
+    int hashCode = Objects.hash(disableCoord, minimumNumberShouldMatch, clauseSets);
     if (hashCode == 0) {
       hashCode = 1;
     }
@@ -443,8 +444,8 @@ public class BooleanQuery extends Query implements Iterable<BooleanClause> {
 
   @Override
   public int hashCode() {
+    // no need for synchronization, in the worst case we would just compute the hash several times.
     if (hashCode == 0) {
-      // no need for synchronization, in the worst case we would just compute the hash several times
       hashCode = computeHashCode();
       assert hashCode != 0;
     }

lucene/core/src/java/org/apache/lucene/search/BoostQuery.java

@@ -58,18 +58,19 @@ public final class BoostQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    BoostQuery that = (BoostQuery) obj;
-    return query.equals(that.query)
-        && Float.floatToIntBits(boost) == Float.floatToIntBits(that.boost);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(BoostQuery other) {
+    return query.equals(other.query) && 
+           Float.floatToIntBits(boost) == Float.floatToIntBits(other.boost);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + query.hashCode();
     h = 31 * h + Float.floatToIntBits(boost);
     return h;

lucene/core/src/java/org/apache/lucene/search/ConstantScoreQuery.java

@@ -162,20 +162,13 @@ public final class ConstantScoreQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (!super.equals(o))
-      return false;
-    if (o instanceof ConstantScoreQuery) {
-      final ConstantScoreQuery other = (ConstantScoreQuery) o;
-      return this.query.equals(other.query);
-    }
-    return false;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           query.equals(((ConstantScoreQuery) other).query);
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + query.hashCode();
+    return 31 * classHash() + query.hashCode();
   }
-
 }

lucene/core/src/java/org/apache/lucene/search/DisjunctionMaxQuery.java

@@ -241,16 +241,18 @@ public final class DisjunctionMaxQuery extends Query implements Iterable<Query>
   }
 
   /** Return true iff we represent the same query as o
-   * @param o another object
+   * @param other another object
    * @return true iff o is a DisjunctionMaxQuery with the same boost and the same subqueries, in the same order, as us
    */
   @Override
-  public boolean equals(Object o) {
-    if (! (o instanceof DisjunctionMaxQuery) ) return false;
-    DisjunctionMaxQuery other = (DisjunctionMaxQuery)o;
-    return super.equals(o)
-            && this.tieBreakerMultiplier == other.tieBreakerMultiplier
-            && Arrays.equals(disjuncts, other.disjuncts);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(DisjunctionMaxQuery other) {
+    return tieBreakerMultiplier == other.tieBreakerMultiplier && 
+           Arrays.equals(disjuncts, other.disjuncts);
   }
 
   /** Compute a hash code for hashing us
@@ -258,7 +260,7 @@ public final class DisjunctionMaxQuery extends Query implements Iterable<Query>
    */
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + Float.floatToIntBits(tieBreakerMultiplier);
     h = 31 * h + Arrays.hashCode(disjuncts);
     return h;

lucene/core/src/java/org/apache/lucene/search/DocValuesRewriteMethod.java

@@ -59,17 +59,14 @@ public final class DocValuesRewriteMethod extends MultiTermQuery.RewriteMethod {
     }
     
     @Override
-    public final boolean equals(final Object o) {
-      if (super.equals(o) == false) {
-        return false;
-      }
-      MultiTermQueryDocValuesWrapper that = (MultiTermQueryDocValuesWrapper) o;
-      return query.equals(that.query);
+    public final boolean equals(final Object other) {
+      return sameClassAs(other) &&
+             query.equals(((MultiTermQueryDocValuesWrapper) other).query);
     }
-    
+
     @Override
     public final int hashCode() {
-      return 31 * super.hashCode() + query.hashCode();
+      return 31 * classHash() + query.hashCode();
     }
     
     /** Returns the field name for this query */
@@ -169,14 +166,9 @@ public final class DocValuesRewriteMethod extends MultiTermQuery.RewriteMethod {
   }
   
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj)
-      return true;
-    if (obj == null)
-      return false;
-    if (getClass() != obj.getClass())
-      return false;
-    return true;
+  public boolean equals(Object other) {
+    return other != null &&
+           getClass() == other.getClass();
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/search/FieldValueQuery.java

@@ -43,17 +43,14 @@ public final class FieldValueQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    final FieldValueQuery that = (FieldValueQuery) obj;
-    return field.equals(that.field);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           field.equals(((FieldValueQuery) other).field);
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + field.hashCode();
+    return 31 * classHash() + field.hashCode();
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/search/MatchAllDocsQuery.java

@@ -71,4 +71,14 @@ public final class MatchAllDocsQuery extends Query {
   public String toString(String field) {
     return "*:*";
   }
+
+  @Override
+  public boolean equals(Object o) {
+    return sameClassAs(o);
+  }
+
+  @Override
+  public int hashCode() {
+    return classHash();
+  }
 }

lucene/core/src/java/org/apache/lucene/search/MatchNoDocsQuery.java

@@ -22,18 +22,27 @@ import java.io.IOException;
 import org.apache.lucene.index.IndexReader;
 
 /**
- * A query that matches no documents.
+     * A query that matches no documents.
  */
 public class MatchNoDocsQuery extends Query {
+  @Override
+  public Query rewrite(IndexReader reader) throws IOException {
+    // Rewrite to an empty BooleanQuery so no Scorer or Weight is required
+    return new BooleanQuery.Builder().build();
+  }
 
-    @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        // Rewrite to an empty BooleanQuery so no Scorer or Weight is required
-        return new BooleanQuery.Builder().build();
-    }
+  @Override
+  public String toString(String field) {
+      return "";
+  }
 
-    @Override
-    public String toString(String field) {
-        return "";
-    }
+  @Override
+  public boolean equals(Object o) {
+    return sameClassAs(o);
+  }
+
+  @Override
+  public int hashCode() {
+    return classHash();
+  }
 }

lucene/core/src/java/org/apache/lucene/search/MultiPhraseQuery.java

@@ -383,20 +383,22 @@ public class MultiPhraseQuery extends Query {
 
   /** Returns true if <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (super.equals(o) == false) {
-      return false;
-    }
-    MultiPhraseQuery other = (MultiPhraseQuery)o;
-    return this.slop == other.slop
-      && termArraysEquals(this.termArrays, other.termArrays) // terms equal implies field equal
-      && Arrays.equals(this.positions, other.positions);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(MultiPhraseQuery other) {
+    return this.slop == other.slop && 
+           termArraysEquals(this.termArrays, other.termArrays) && /* terms equal implies field equal */ 
+           Arrays.equals(this.positions, other.positions);
+
   }
 
   /** Returns a hash code value for this object.*/
   @Override
   public int hashCode() {
-    return super.hashCode()
+    return classHash()
       ^ slop
       ^ termArraysHashCode() // terms equal implies field equal
       ^ Arrays.hashCode(positions);

lucene/core/src/java/org/apache/lucene/search/MultiTermQuery.java

@@ -332,27 +332,20 @@ public abstract class MultiTermQuery extends Query {
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = 1;
+    int result = classHash();
     result = prime * result + rewriteMethod.hashCode();
-    if (field != null) result = prime * result + field.hashCode();
+    result = prime * result + field.hashCode();
     return result;
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj)
-      return true;
-    if (obj == null)
-      return false;
-    if (getClass() != obj.getClass())
-      return false;
-    MultiTermQuery other = (MultiTermQuery) obj;
-    if (!super.equals(obj))
-      return false;
-    if (!rewriteMethod.equals(other.rewriteMethod)) {
-      return false;
-    }
-    return (other.field == null ? field == null : other.field.equals(field));
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(MultiTermQuery other) {
+    return rewriteMethod.equals(other.rewriteMethod) && 
+           field.equals(other.field);
   }
- 
 }

lucene/core/src/java/org/apache/lucene/search/MultiTermQueryConstantScoreWrapper.java

@@ -91,17 +91,14 @@ final class MultiTermQueryConstantScoreWrapper<Q extends MultiTermQuery> extends
   }
 
   @Override
-  public final boolean equals(final Object o) {
-    if (super.equals(o) == false) {
-      return false;
-    }
-    final MultiTermQueryConstantScoreWrapper<?> that = (MultiTermQueryConstantScoreWrapper<?>) o;
-    return this.query.equals(that.query);
+  public final boolean equals(final Object other) {
+    return sameClassAs(other) &&
+           query.equals(((MultiTermQueryConstantScoreWrapper<?>) other).query);
   }
 
   @Override
   public final int hashCode() {
-    return 31 * super.hashCode() + query.hashCode();
+    return 31 * classHash() + query.hashCode();
   }
 
   /** Returns the encapsulated query */

lucene/core/src/java/org/apache/lucene/search/NGramPhraseQuery.java

@@ -78,17 +78,19 @@ public class NGramPhraseQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (super.equals(o) == false) {
-      return false;
-    }
-    NGramPhraseQuery other = (NGramPhraseQuery) o;
-    return n == other.n && phraseQuery.equals(other.phraseQuery);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(NGramPhraseQuery other) {
+    return n == other.n && 
+           phraseQuery.equals(other.phraseQuery);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + phraseQuery.hashCode();
     h = 31 * h + n;
     return h;

lucene/core/src/java/org/apache/lucene/search/PhraseQuery.java

@@ -561,20 +561,21 @@ public class PhraseQuery extends Query {
 
   /** Returns true iff <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (super.equals(o) == false) {
-      return false;
-    }
-    PhraseQuery that = (PhraseQuery) o;
-    return slop == that.slop
-        && Arrays.equals(terms, that.terms)
-        && Arrays.equals(positions, that.positions);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(PhraseQuery other) {
+    return slop == other.slop && 
+           Arrays.equals(terms, other.terms) && 
+           Arrays.equals(positions, other.positions);
   }
 
   /** Returns a hash code value for this object.*/
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + slop;
     h = 31 * h + Arrays.hashCode(terms);
     h = 31 * h + Arrays.hashCode(positions);

lucene/core/src/java/org/apache/lucene/search/PointInSetQuery.java

@@ -305,7 +305,7 @@ public abstract class PointInSetQuery extends Query {
 
   @Override
   public final int hashCode() {
-    int hash = super.hashCode();
+    int hash = classHash();
     hash = 31 * hash + field.hashCode();
     hash = 31 * hash + sortedPackedPointsHashCode;
     hash = 31 * hash + numDims;
@@ -315,16 +315,16 @@ public abstract class PointInSetQuery extends Query {
 
   @Override
   public final boolean equals(Object other) {
-    if (super.equals(other)) {
-      final PointInSetQuery q = (PointInSetQuery) other;
-      return q.field.equals(field) &&
-        q.numDims == numDims &&
-        q.bytesPerDim == bytesPerDim &&
-        q.sortedPackedPointsHashCode == sortedPackedPointsHashCode &&
-        q.sortedPackedPoints.equals(sortedPackedPoints);
-    }
-
-    return false;
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(PointInSetQuery other) {
+    return other.field.equals(field) &&
+           other.numDims == numDims &&
+           other.bytesPerDim == bytesPerDim &&
+           other.sortedPackedPointsHashCode == sortedPackedPointsHashCode &&
+           other.sortedPackedPoints.equals(sortedPackedPoints);
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/search/PointRangeQuery.java

@@ -220,7 +220,7 @@ public abstract class PointRangeQuery extends Query {
 
   @Override
   public final int hashCode() {
-    int hash = super.hashCode();
+    int hash = classHash();
     hash = 31 * hash + field.hashCode();
     hash = 31 * hash + Arrays.hashCode(lowerPoint);
     hash = 31 * hash + Arrays.hashCode(upperPoint);
@@ -230,33 +230,17 @@ public abstract class PointRangeQuery extends Query {
   }
 
   @Override
-  public final boolean equals(Object other) {
-    if (super.equals(other) == false) {
-      return false;
-    }
+  public final boolean equals(Object o) {
+    return sameClassAs(o) &&
+           equalsTo(getClass().cast(o));
+  }
 
-    final PointRangeQuery q = (PointRangeQuery) other;
-    if (field.equals(q.field) == false) {
-      return false;
-    }
-
-    if (q.numDims != numDims) {
-      return false;
-    }
-
-    if (q.bytesPerDim != bytesPerDim) {
-      return false;
-    }
-
-    if (Arrays.equals(lowerPoint, q.lowerPoint) == false) {
-      return false;
-    }
-    
-    if (Arrays.equals(upperPoint, q.upperPoint) == false) {
-      return false;
-    }
-
-    return true;
+  private boolean equalsTo(PointRangeQuery other) {
+    return Objects.equals(field, other.field) &&
+           numDims == other.numDims &&
+           bytesPerDim == other.bytesPerDim &&
+           Arrays.equals(lowerPoint, other.lowerPoint) &&
+           Arrays.equals(upperPoint, other.upperPoint);
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/search/Query.java

@@ -74,15 +74,50 @@ public abstract class Query {
     return this;
   }
 
+  /**
+   * Override and implement query instance equivalence properly in a subclass. 
+   * This is required so that {@link QueryCache} works properly.
+   * 
+   * Typically a query will be equal to another only if it's an instance of 
+   * the same class and its document-filtering properties are identical that other
+   * instance. Utility methods are provided for certain repetitive code. 
+   * 
+   * @see #sameClassAs(Object)
+   * @see #classHash()
+   */
   @Override
-  public int hashCode() {
-    return getClass().hashCode();
+  public abstract boolean equals(Object obj);
+
+  /**
+   * Override and implement query hash code properly in a subclass. 
+   * This is required so that {@link QueryCache} works properly.
+   * 
+   * @see #equals(Object)
+   */
+  @Override
+  public abstract int hashCode();
+
+  /**
+   * Utility method to check whether <code>other</code> is not null and is exactly 
+   * of the same class as this object's class.
+   * 
+   * When this method is used in an implementation of {@link #equals(Object)},
+   * consider using {@link #classHash()} in the implementation
+   * of {@link #hashCode} to differentiate different class
+   */
+  protected final boolean sameClassAs(Object other) {
+    return other != null && getClass() == other.getClass();
   }
 
-  @Override
-  public boolean equals(Object obj) {
-    if (obj == null)
-      return false;
-    return getClass() == obj.getClass();
+  private final int CLASS_NAME_HASH = getClass().getName().hashCode();
+
+  /**
+   * Provides a constant integer for a given class, derived from the name of the class.
+   * The rationale for not using just {@link Class#hashCode()} is that classes may be
+   * assigned different hash codes for each execution and we want hashes to be possibly
+   * consistent to facilitate debugging.    
+   */
+  protected final int classHash() {
+    return CLASS_NAME_HASH;
   }
 }

lucene/core/src/java/org/apache/lucene/search/SynonymQuery.java

@@ -88,20 +88,13 @@ public final class SynonymQuery extends Query {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = super.hashCode();
-    result = prime * result + Arrays.hashCode(terms);
-    return result;
+    return 31 * classHash() + Arrays.hashCode(terms);
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    SynonymQuery other = (SynonymQuery) obj;
-    if (!Arrays.equals(terms, other.terms)) return false;
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           Arrays.equals(terms, ((SynonymQuery) other).terms);
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/search/TermQuery.java

@@ -211,14 +211,13 @@ public class TermQuery extends Query {
 
   /** Returns true iff <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (!(o instanceof TermQuery)) return false;
-    TermQuery other = (TermQuery) o;
-    return super.equals(o) && this.term.equals(other.term);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           term.equals(((TermQuery) other).term);
   }
 
   @Override
   public int hashCode() {
-    return super.hashCode() ^ term.hashCode();
+    return classHash() ^ term.hashCode();
   }
 }

lucene/core/src/java/org/apache/lucene/search/spans/FieldMaskingSpanQuery.java

@@ -95,8 +95,6 @@ public final class FieldMaskingSpanQuery extends SpanQuery {
 
   @Override
   public Query rewrite(IndexReader reader) throws IOException {
-    FieldMaskingSpanQuery clone = null;
-
     SpanQuery rewritten = (SpanQuery) maskedQuery.rewrite(reader);
     if (rewritten != maskedQuery) {
       return new FieldMaskingSpanQuery(rewritten, field);
@@ -117,20 +115,20 @@ public final class FieldMaskingSpanQuery extends SpanQuery {
   }
   
   @Override
-  public boolean equals(Object o) {
-    if (! super.equals(o)) {
-      return false;
-    }
-    FieldMaskingSpanQuery other = (FieldMaskingSpanQuery) o;
-    return (this.getField().equals(other.getField())
-            && this.getMaskedQuery().equals(other.getMaskedQuery()));
-
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
   }
   
+  private boolean equalsTo(FieldMaskingSpanQuery other) {
+    return getField().equals(other.getField()) && 
+           getMaskedQuery().equals(other.getMaskedQuery());
+  }
+
   @Override
   public int hashCode() {
-    return super.hashCode()
-          ^ getMaskedQuery().hashCode()
-          ^ getField().hashCode();
+    return classHash() ^ 
+           getMaskedQuery().hashCode() ^ 
+           getField().hashCode();
   }
 }

lucene/core/src/java/org/apache/lucene/search/spans/SpanBoostQuery.java

@@ -31,7 +31,6 @@ import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.Scorer;
 
 /**
  * Counterpart of {@link BoostQuery} for spans.
@@ -63,18 +62,19 @@ public final class SpanBoostQuery extends SpanQuery {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    SpanBoostQuery that = (SpanBoostQuery) obj;
-    return query.equals(that.query)
-        && Float.floatToIntBits(boost) == Float.floatToIntBits(that.boost);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(SpanBoostQuery other) {
+    return query.equals(other.query) && 
+           Float.floatToIntBits(boost) == Float.floatToIntBits(other.boost);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + query.hashCode();
     h = 31 * h + Float.floatToIntBits(boost);
     return h;

lucene/core/src/java/org/apache/lucene/search/spans/SpanContainQuery.java

@@ -129,17 +129,19 @@ abstract class SpanContainQuery extends SpanQuery implements Cloneable {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (! super.equals(o)) {
-      return false;
-    }
-    SpanContainQuery other = (SpanContainQuery)o;
-    return big.equals(other.big) && little.equals(other.little);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  } 
+  
+  private boolean equalsTo(SpanContainQuery other) {
+    return big.equals(other.big) && 
+           little.equals(other.little);
   }
 
   @Override
   public int hashCode() {
-    int h = Integer.rotateLeft(super.hashCode(), 1);
+    int h = Integer.rotateLeft(classHash(), 1);
     h ^= big.hashCode();
     h = Integer.rotateLeft(h, 1);
     h ^= little.hashCode();

lucene/core/src/java/org/apache/lucene/search/spans/SpanMultiTermQueryWrapper.java

@@ -123,19 +123,13 @@ public class SpanMultiTermQueryWrapper<Q extends MultiTermQuery> extends SpanQue
   
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = super.hashCode();
-    result = prime * result + query.hashCode();
-    return result;
+    return classHash() * 31 + query.hashCode();
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (! super.equals(obj)) {
-      return false;
-    }
-    SpanMultiTermQueryWrapper<?> other = (SpanMultiTermQueryWrapper<?>) obj;
-    return query.equals(other.query);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           query.equals(((SpanMultiTermQueryWrapper<?>) other).query);
   }
 
   /** Abstract class that defines how the query is rewritten. */

lucene/core/src/java/org/apache/lucene/search/spans/SpanNearQuery.java

@@ -253,22 +253,21 @@ public class SpanNearQuery extends SpanQuery implements Cloneable {
     return super.rewrite(reader);
   }
 
-  /** Returns true iff <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (! super.equals(o)) {
-      return false;
-    }
-    final SpanNearQuery spanNearQuery = (SpanNearQuery) o;
-
-    return (inOrder == spanNearQuery.inOrder)
-        && (slop == spanNearQuery.slop)
-        && clauses.equals(spanNearQuery.clauses);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(SpanNearQuery other) {
+    return inOrder == other.inOrder && 
+           slop == other.slop &&
+           clauses.equals(other.clauses);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result ^= clauses.hashCode();
     result += slop;
     int fac = 1 + (inOrder ? 8 : 4);
@@ -321,6 +320,25 @@ public class SpanNearQuery extends SpanQuery implements Cloneable {
 
       }
     }
+
+    @Override
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+    
+    private boolean equalsTo(SpanGapQuery other) {
+      return width == other.width &&
+             field.equals(other.field);
+    }
+
+    @Override
+    public int hashCode() {
+      int result = classHash();
+      result -= 7 * width;
+      return result * 15 - field.hashCode();
+    }
+
   }
 
   static class GapSpans extends Spans {

lucene/core/src/java/org/apache/lucene/search/spans/SpanNotQuery.java

@@ -200,20 +200,21 @@ public final class SpanNotQuery extends SpanQuery {
   }
     /** Returns true iff <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (!super.equals(o))
-      return false;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  } 
 
-    SpanNotQuery other = (SpanNotQuery)o;
-    return this.include.equals(other.include)
-            && this.exclude.equals(other.exclude)
-            && this.pre == other.pre
-            && this.post == other.post;
+  private boolean equalsTo(SpanNotQuery other) { 
+    return include.equals(other.include) && 
+           exclude.equals(other.exclude) && 
+           pre == other.pre && 
+           post == other.post;
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = Integer.rotateLeft(h, 1);
     h ^= include.hashCode();
     h = Integer.rotateLeft(h, 1);

lucene/core/src/java/org/apache/lucene/search/spans/SpanOrQuery.java

@@ -103,19 +103,14 @@ public final class SpanOrQuery extends SpanQuery {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (! super.equals(o)) {
-      return false;
-    }
-    final SpanOrQuery that = (SpanOrQuery) o;
-    return clauses.equals(that.clauses);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           clauses.equals(((SpanOrQuery) other).clauses);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
-    h = (h * 7) ^ clauses.hashCode();
-    return h;
+    return classHash() ^ clauses.hashCode();
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/search/spans/SpanPositionCheckQuery.java

@@ -120,18 +120,15 @@ public abstract class SpanPositionCheckQuery extends SpanQuery implements Clonea
     return super.rewrite(reader);
   }
 
-  /** Returns true iff <code>o</code> is equal to this. */
+  /** Returns true iff <code>other</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (! super.equals(o)) {
-      return false;
-    }
-    SpanPositionCheckQuery spcq = (SpanPositionCheckQuery) o;
-    return match.equals(spcq.match);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           match.equals(((SpanPositionCheckQuery) other).match);
   }
 
   @Override
   public int hashCode() {
-    return match.hashCode() ^ super.hashCode();
+    return classHash() ^ match.hashCode();
   }
 }

lucene/core/src/java/org/apache/lucene/search/spans/SpanTermQuery.java

@@ -163,19 +163,13 @@ public class SpanTermQuery extends SpanQuery {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = super.hashCode();
-    result = prime * result + term.hashCode();
-    return result;
+    return classHash() ^ term.hashCode();
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (! super.equals(obj)) {
-      return false;
-    }
-    SpanTermQuery other = (SpanTermQuery) obj;
-    return term.equals(other.term);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           term.equals(((SpanTermQuery) other).term);
   }
 
 }

lucene/core/src/test/org/apache/lucene/search/JustCompileSearch.java

@@ -28,7 +28,7 @@ import org.apache.lucene.util.PriorityQueue;
 
 /**
  * Holds all implementations of classes in the o.a.l.search package as a
- * back-compatibility test. It does not run any tests per-se, however if 
+ * back-compatibility test. It does not run any tests per-se, however if
  * someone adds a method to an interface or abstract method to an abstract
  * class, one of the implementations here will fail to compile and so we know
  * back-compat policy was violated.
@@ -59,7 +59,7 @@ final class JustCompileSearch {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
   }
-  
+
   static final class JustCompileDocIdSet extends DocIdSet {
 
     @Override
@@ -84,18 +84,18 @@ final class JustCompileSearch {
     public int nextDoc() {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
     @Override
     public int advance(int target) {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
     @Override
     public long cost() {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
   }
-  
+
   static final class JustCompileFieldComparator extends FieldComparator<Object> {
 
     @Override
@@ -126,7 +126,7 @@ final class JustCompileSearch {
         int sortPos, boolean reversed) {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
   }
 
   static final class JustCompileFilteredDocIdSetIterator extends FilteredDocIdSetIterator {
@@ -139,7 +139,7 @@ final class JustCompileSearch {
     protected boolean match(int doc) {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
     @Override
     public long cost() {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
@@ -152,9 +152,18 @@ final class JustCompileSearch {
     public String toString(String field) {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
+    @Override
+    public boolean equals(Object obj) {
+      throw new UnsupportedOperationException(UNSUPPORTED_MSG);
+    }
+
+    @Override
+    public int hashCode() {
+      throw new UnsupportedOperationException(UNSUPPORTED_MSG);
+    }
   }
-  
+
   static final class JustCompileScorer extends Scorer {
 
     protected JustCompileScorer(Weight weight) {
@@ -165,7 +174,7 @@ final class JustCompileSearch {
     public float score() {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
     @Override
     public int freq() {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
@@ -181,7 +190,7 @@ final class JustCompileSearch {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
   }
-  
+
   static final class JustCompileSimilarity extends Similarity {
 
     @Override
@@ -264,5 +273,5 @@ final class JustCompileSearch {
     }
 
   }
-  
+
 }

lucene/core/src/test/org/apache/lucene/search/TestBooleanScorer.java

@@ -39,7 +39,7 @@ import org.apache.lucene.util.TestUtil;
 
 public class TestBooleanScorer extends LuceneTestCase {
   private static final String FIELD = "category";
-  
+
   public void testMethod() throws Exception {
     Directory directory = newDirectory();
 
@@ -122,6 +122,16 @@ public class TestBooleanScorer extends LuceneTestCase {
         }
       };
     }
+
+    @Override
+    public boolean equals(Object obj) {
+      return this == obj;
+    }
+
+    @Override
+    public int hashCode() {
+      return System.identityHashCode(this);
+    }
   }
 
   /** Make sure BooleanScorer can embed another

lucene/core/src/test/org/apache/lucene/search/TestConstantScoreQuery.java

@@ -148,17 +148,14 @@ public class TestConstantScoreQuery extends LuceneTestCase {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      QueryWrapper that = (QueryWrapper) obj;
-      return in.equals(that.in);
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             in.equals(((QueryWrapper) other).in);
     }
 
     @Override
     public int hashCode() {
-      return 31 * super.hashCode() + in.hashCode();
+      return 31 * classHash() + in.hashCode();
     }
   }
 

lucene/core/src/test/org/apache/lucene/search/TestLRUQueryCache.java

@@ -357,11 +357,9 @@ public class TestLRUQueryCache extends LuceneTestCase {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (obj instanceof DummyQuery == false) {
-        return false;
-      }
-      return id == ((DummyQuery) obj).id;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             id == ((DummyQuery) other).id;
     }
 
     @Override
@@ -950,9 +948,14 @@ public class TestLRUQueryCache extends LuceneTestCase {
 
     @Override
     public int hashCode() {
-      return super.hashCode() ^ i[0];
+      return classHash() ^ i[0];
     }
 
+    @Override
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             i[0] == ((BadQuery) other).i[0];
+    }
   }
 
   public void testDetectMutatedQueries() throws IOException {

lucene/core/src/test/org/apache/lucene/search/TestNeedsScores.java

@@ -19,6 +19,7 @@ package org.apache.lucene.search;
 
 import java.io.IOException;
 import java.util.Set;
+import java.util.Objects;
 
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
@@ -95,7 +96,7 @@ public class TestNeedsScores extends LuceneTestCase {
     final boolean value;
     
     AssertNeedsScores(Query in, boolean value) {
-      this.in = in;
+      this.in = Objects.requireNonNull(in);
       this.value = value;
     }
 
@@ -144,23 +145,21 @@ public class TestNeedsScores extends LuceneTestCase {
     @Override
     public int hashCode() {
       final int prime = 31;
-      int result = super.hashCode();
-      result = prime * result + ((in == null) ? 0 : in.hashCode());
+      int result = classHash();
+      result = prime * result + in.hashCode();
       result = prime * result + (value ? 1231 : 1237);
       return result;
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (this == obj) return true;
-      if (!super.equals(obj)) return false;
-      if (getClass() != obj.getClass()) return false;
-      AssertNeedsScores other = (AssertNeedsScores) obj;
-      if (in == null) {
-        if (other.in != null) return false;
-      } else if (!in.equals(other.in)) return false;
-      if (value != other.value) return false;
-      return true;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+    
+    private boolean equalsTo(AssertNeedsScores other) {
+      return in.equals(other.in) && 
+             value == other.value;
     }
 
     @Override

lucene/core/src/test/org/apache/lucene/search/TestQueryRescorer.java

@@ -503,30 +503,27 @@ public class TestQueryRescorer extends LuceneTestCase {
     }
 
     @Override
-    public boolean equals(Object o) {
-      if ((o instanceof FixedScoreQuery) == false) {
-        return false;
-      }
-      FixedScoreQuery other = (FixedScoreQuery) o;
-      return super.equals(o) &&
-        reverse == other.reverse &&
-        Arrays.equals(idToNum, other.idToNum);
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(FixedScoreQuery other) {
+      return reverse == other.reverse && 
+             Arrays.equals(idToNum, other.idToNum);
+    }
+
+    @Override
+    public int hashCode() {
+      int hash = classHash();
+      hash = 31 * hash + (reverse ? 0 : 1);
+      hash = 31 * hash + Arrays.hashCode(idToNum);
+      return hash;
     }
 
     @Override
     public Query clone() {
       return new FixedScoreQuery(idToNum, reverse);
     }
-
-    @Override
-    public int hashCode() {
-      int PRIME = 31;
-      int hash = super.hashCode();
-      if (reverse) {
-        hash = PRIME * hash + 3623;
-      }
-      hash = PRIME * hash + Arrays.hashCode(idToNum);
-      return hash;
-    }
   }
 }

lucene/core/src/test/org/apache/lucene/search/TestScorerPerf.java

@@ -165,16 +165,14 @@ public class TestScorerPerf extends LuceneTestCase {
     }
     
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      return docs == ((BitSetQuery) obj).docs;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             docs.equals(((BitSetQuery) other).docs);
     }
 
     @Override
     public int hashCode() {
-      return 31 * super.hashCode() + System.identityHashCode(docs);
+      return 31 * classHash() + docs.hashCode();
     }
   }
 

lucene/core/src/test/org/apache/lucene/search/TestSortRandom.java

@@ -257,19 +257,21 @@ public class TestSortRandom extends LuceneTestCase {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      RandomQuery other = (RandomQuery) obj;
-      return seed == other.seed && docValues == other.docValues;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+    
+    private boolean equalsTo(RandomQuery other) {
+      return seed == other.seed && 
+             docValues == other.docValues;
     }
 
     @Override
     public int hashCode() {
       int h = Objects.hash(seed, density);
       h = 31 * h + System.identityHashCode(docValues);
-      h = 31 * h + super.hashCode();
+      h = 31 * h + classHash();
       return h;
     }
   }

lucene/core/src/test/org/apache/lucene/search/spans/JustCompileSearchSpans.java

@@ -48,7 +48,7 @@ final class JustCompileSearchSpans {
     public int advance(int target) throws IOException {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
     @Override
     public int startPosition() {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
@@ -101,7 +101,17 @@ final class JustCompileSearchSpans {
     public String toString(String field) {
       throw new UnsupportedOperationException(UNSUPPORTED_MSG);
     }
-    
+
+    @Override
+    public boolean equals(Object o) {
+      throw new UnsupportedOperationException(UNSUPPORTED_MSG);
+    }
+
+    @Override
+    public int hashCode() {
+      throw new UnsupportedOperationException(UNSUPPORTED_MSG);
+    }
+
   }
 
 }

lucene/facet/src/java/org/apache/lucene/facet/DrillDownQuery.java

@@ -122,19 +122,20 @@ public final class DrillDownQuery extends Query {
   
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + Objects.hash(baseQuery, dimQueries);
+    return classHash() + Objects.hash(baseQuery, dimQueries);
   }
-  
+
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    DrillDownQuery other = (DrillDownQuery) obj;
-    return Objects.equals(baseQuery, other.baseQuery)
-        && dimQueries.equals(other.dimQueries);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
   }
-  
+
+  private boolean equalsTo(DrillDownQuery other) {
+    return Objects.equals(baseQuery, other.baseQuery) && 
+           dimQueries.equals(other.dimQueries);
+  }
+
   @Override
   public Query rewrite(IndexReader r) throws IOException {
     BooleanQuery rewritten = getBooleanQuery();

lucene/facet/src/java/org/apache/lucene/facet/DrillSidewaysQuery.java

@@ -161,29 +161,24 @@ class DrillSidewaysQuery extends Query {
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = super.hashCode();
-    result = prime * result + ((baseQuery == null) ? 0 : baseQuery.hashCode());
-    result = prime * result
-        + ((drillDownCollector == null) ? 0 : drillDownCollector.hashCode());
+    int result = classHash();
+    result = prime * result + Objects.hashCode(baseQuery);
+    result = prime * result + Objects.hashCode(drillDownCollector);
     result = prime * result + Arrays.hashCode(drillDownQueries);
     result = prime * result + Arrays.hashCode(drillSidewaysCollectors);
     return result;
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    DrillSidewaysQuery other = (DrillSidewaysQuery) obj;
-    if (baseQuery == null) {
-      if (other.baseQuery != null) return false;
-    } else if (!baseQuery.equals(other.baseQuery)) return false;
-    if (drillDownCollector == null) {
-      if (other.drillDownCollector != null) return false;
-    } else if (!drillDownCollector.equals(other.drillDownCollector)) return false;
-    if (!Arrays.equals(drillDownQueries, other.drillDownQueries)) return false;
-    if (!Arrays.equals(drillSidewaysCollectors, other.drillSidewaysCollectors)) return false;
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(DrillSidewaysQuery other) {
+    return Objects.equals(baseQuery, other.baseQuery) &&
+           Objects.equals(drillDownCollector, other.drillDownCollector) &&
+           Arrays.equals(drillDownQueries, other.drillDownQueries) &&
+           Arrays.equals(drillSidewaysCollectors, other.drillSidewaysCollectors);
   }
 }

lucene/facet/src/java/org/apache/lucene/facet/range/DoubleRange.java

@@ -104,19 +104,20 @@ public final class DoubleRange extends Range {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      ValueSourceQuery other = (ValueSourceQuery) obj;
-      return range.equals(other.range)
-          && Objects.equals(fastMatchQuery, other.fastMatchQuery)
-          && valueSource.equals(other.valueSource);
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(ValueSourceQuery other) {
+      return range.equals(other.range) && 
+             Objects.equals(fastMatchQuery, other.fastMatchQuery) && 
+             valueSource.equals(other.valueSource);
     }
 
     @Override
     public int hashCode() {
-      return 31 * Objects.hash(range, fastMatchQuery, valueSource) + super.hashCode();
+      return classHash() + 31 * Objects.hash(range, fastMatchQuery, valueSource);
     }
 
     @Override

lucene/facet/src/java/org/apache/lucene/facet/range/LongRange.java

@@ -96,19 +96,20 @@ public final class LongRange extends Range {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      ValueSourceQuery other = (ValueSourceQuery) obj;
-      return range.equals(other.range)
-          && Objects.equals(fastMatchQuery, other.fastMatchQuery)
-          && valueSource.equals(other.valueSource);
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(ValueSourceQuery other) {
+      return range.equals(other.range) && 
+             Objects.equals(fastMatchQuery, other.fastMatchQuery) && 
+             valueSource.equals(other.valueSource);
     }
 
     @Override
     public int hashCode() {
-      return 31 * Objects.hash(range, fastMatchQuery, valueSource) + super.hashCode();
+      return classHash() + 31 * Objects.hash(range, fastMatchQuery, valueSource);
     }
 
     @Override

lucene/facet/src/test/org/apache/lucene/facet/TestDrillSideways.java

@@ -117,7 +117,7 @@ public class TestDrillSideways extends FacetTestCase {
 
     //  case: drill-down on a single field; in this
     // case the drill-sideways + drill-down counts ==
-    // drill-down of just the query: 
+    // drill-down of just the query:
     DrillDownQuery ddq = new DrillDownQuery(config);
     ddq.add("Author", "Lisa");
     DrillSidewaysResult r = ds.search(null, ddq, 10);
@@ -361,7 +361,7 @@ public class TestDrillSideways extends FacetTestCase {
     String contentToken;
 
     public Doc() {}
-    
+
     // -1 if the doc is missing this dim, else the index
     // -into the values for this dim:
     int[] dims;
@@ -437,7 +437,7 @@ public class TestDrillSideways extends FacetTestCase {
         if (s.length() > 0) {
           values.add(s);
         }
-      } 
+      }
       dimValues[dim] = values.toArray(new String[values.size()]);
       valueCount *= 2;
     }
@@ -560,7 +560,7 @@ public class TestDrillSideways extends FacetTestCase {
 
     final SortedSetDocValuesReaderState sortedSetDVState;
     IndexSearcher s = newSearcher(r);
-    
+
     if (doUseDV) {
       sortedSetDVState = new DefaultSortedSetDocValuesReaderState(s.getIndexReader());
     } else {
@@ -669,7 +669,7 @@ public class TestDrillSideways extends FacetTestCase {
                   public int length() {
                     return context.reader().maxDoc();
                   }
-                  
+
                 };
               }
             };
@@ -680,6 +680,15 @@ public class TestDrillSideways extends FacetTestCase {
             return "drillSidewaysTestFilter";
           }
 
+          @Override
+          public boolean equals(Object o) {
+            return o == this;
+          }
+
+          @Override
+          public int hashCode() {
+            return System.identityHashCode(this);
+          }
         };
       } else {
         filter = null;
@@ -823,7 +832,7 @@ public class TestDrillSideways extends FacetTestCase {
     int[] uniqueCounts;
     public TestFacetResult() {}
   }
-  
+
   private int[] getTopNOrds(final int[] counts, final String[] values, int topN) {
     final int[] ids = new int[counts.length];
     for(int i=0;i<ids.length;i++) {
@@ -1050,7 +1059,7 @@ public class TestDrillSideways extends FacetTestCase {
             if (expected.counts[dim][i] != 0) {
               System.out.println("        " + idx + ": " + new BytesRef(value) + ": " + expected.counts[dim][i]);
               idx++;
-            } 
+            }
           }
         }
 
@@ -1084,7 +1093,7 @@ public class TestDrillSideways extends FacetTestCase {
     DrillSideways ds = new DrillSideways(searcher, config, taxoReader);
     DrillDownQuery ddq = new DrillDownQuery(config);
     ddq.add("Author", "Lisa");
-    
+
     DrillSidewaysResult r = ds.search(ddq, 10); // this used to fail on IllegalArgEx
     assertEquals(0, r.hits.totalHits);
 

lucene/facet/src/test/org/apache/lucene/facet/range/TestRangeFacetCounts.java

@@ -658,17 +658,14 @@ public class TestRangeFacetCounts extends FacetTestCase {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      UsedQuery that = (UsedQuery) obj;
-      return in.equals(that.in);
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             in.equals(((UsedQuery) other).in);
     }
 
     @Override
     public int hashCode() {
-      return 31 * super.hashCode() + in.hashCode();
+      return classHash() + in.hashCode();
     }
 
     @Override

lucene/highlighter/src/test/org/apache/lucene/search/highlight/HighlighterTest.java

@@ -222,8 +222,8 @@ public class HighlighterTest extends BaseTokenStreamTestCase implements Formatte
     fragment = highlighter.getBestFragment(stream, storedField);
     assertEquals("This piece of text refers to Kennedy at the beginning then has a longer piece of text that is <B>very</B>", fragment);
   }
-  
-  public void testHighlightUnknowQueryAfterRewrite() throws IOException, InvalidTokenOffsetsException {
+
+  public void testHighlightUnknownQueryAfterRewrite() throws IOException, InvalidTokenOffsetsException {
     Query query = new Query() {
       
       @Override
@@ -242,12 +242,12 @@ public class HighlighterTest extends BaseTokenStreamTestCase implements Formatte
 
       @Override
       public int hashCode() {
-        return 31 * super.hashCode();
+        return System.identityHashCode(this);
       }
 
       @Override
       public boolean equals(Object obj) {
-        return super.equals(obj);
+        return obj == this;
       }
     };
 

lucene/highlighter/src/test/org/apache/lucene/search/highlight/custom/HighlightCustomQueryTest.java

@@ -38,6 +38,7 @@ import org.apache.lucene.util.LuceneTestCase;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Tests the extensibility of {@link WeightedSpanTermExtractor} and
@@ -161,7 +162,6 @@ public class HighlightCustomQueryTest extends LuceneTestCase {
     private final Term term;
 
     public CustomQuery(Term term) {
-      super();
       this.term = term;
     }
 
@@ -177,28 +177,13 @@ public class HighlightCustomQueryTest extends LuceneTestCase {
 
     @Override
     public int hashCode() {
-      final int prime = 31;
-      int result = super.hashCode();
-      result = prime * result + ((term == null) ? 0 : term.hashCode());
-      return result;
+      return classHash() + Objects.hashCode(term);
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (this == obj)
-        return true;
-      if (!super.equals(obj))
-        return false;
-      if (getClass() != obj.getClass())
-        return false;
-      CustomQuery other = (CustomQuery) obj;
-      if (term == null) {
-        if (other.term != null)
-          return false;
-      } else if (!term.equals(other.term))
-        return false;
-      return true;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             Objects.equals(term, ((CustomQuery) other).term);
     }
-
   }
 }

lucene/highlighter/src/test/org/apache/lucene/search/vectorhighlight/FieldQueryTest.java

@@ -61,7 +61,7 @@ public class FieldQueryTest extends AbstractTestCase {
 
     Query booleanQuery = booleanQueryB.build();
     booleanQuery = new BoostQuery(booleanQuery, boost);
-    
+
     FieldQuery fq = new FieldQuery(booleanQuery, true, true );
     Set<Query> flatQueries = new HashSet<>();
     fq.flatten(booleanQuery, reader, flatQueries, 1f);
@@ -235,14 +235,14 @@ public class FieldQueryTest extends AbstractTestCase {
   public void testGetFieldTermMap() throws Exception {
     Query query = tq( "a" );
     FieldQuery fq = new FieldQuery( query, true, true );
-    
+
     QueryPhraseMap pqm = fq.getFieldTermMap( F, "a" );
     assertNotNull( pqm );
     assertTrue( pqm.isTerminal() );
-    
+
     pqm = fq.getFieldTermMap( F, "b" );
     assertNull( pqm );
-    
+
     pqm = fq.getFieldTermMap( F1, "a" );
     assertNull( pqm );
   }
@@ -296,10 +296,10 @@ public class FieldQueryTest extends AbstractTestCase {
     termSet = fq.getTermSet( "y" );
     assertNull( termSet );
   }
-  
+
   public void testQueryPhraseMap1Term() throws Exception {
     Query query = tq( "a" );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query, true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -311,7 +311,7 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm.subMap.get( "a" ) != null );
     assertTrue( qpm.subMap.get( "a" ).terminal );
     assertEquals( 1F, qpm.subMap.get( "a" ).boost, 0);
-    
+
     // phraseHighlight = true, fieldMatch = false
     fq = new FieldQuery( query, true, false );
     map = fq.rootMaps;
@@ -323,7 +323,7 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm.subMap.get( "a" ) != null );
     assertTrue( qpm.subMap.get( "a" ).terminal );
     assertEquals( 1F, qpm.subMap.get( "a" ).boost, 0);
-    
+
     // phraseHighlight = false, fieldMatch = true
     fq = new FieldQuery( query, false, true );
     map = fq.rootMaps;
@@ -335,7 +335,7 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm.subMap.get( "a" ) != null );
     assertTrue( qpm.subMap.get( "a" ).terminal );
     assertEquals( 1F, qpm.subMap.get( "a" ).boost, 0);
-    
+
     // phraseHighlight = false, fieldMatch = false
     fq = new FieldQuery( query, false, false );
     map = fq.rootMaps;
@@ -347,7 +347,7 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm.subMap.get( "a" ) != null );
     assertTrue( qpm.subMap.get( "a" ).terminal );
     assertEquals( 1F, qpm.subMap.get( "a" ).boost, 0);
-    
+
     // boost != 1
     query = tq( 2, "a" );
     fq = new FieldQuery( query, true, true );
@@ -355,10 +355,10 @@ public class FieldQueryTest extends AbstractTestCase {
     qpm = map.get( F );
     assertEquals( 2F, qpm.subMap.get( "a" ).boost, 0);
   }
-  
+
   public void testQueryPhraseMap1Phrase() throws Exception {
     Query query = pqF( "a", "b" );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query, true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -375,7 +375,7 @@ public class FieldQueryTest extends AbstractTestCase {
     QueryPhraseMap qpm3 = qpm2.subMap.get( "b" );
     assertTrue( qpm3.terminal );
     assertEquals( 1F, qpm3.boost, 0);
-    
+
     // phraseHighlight = true, fieldMatch = false
     fq = new FieldQuery( query, true, false );
     map = fq.rootMaps;
@@ -392,7 +392,7 @@ public class FieldQueryTest extends AbstractTestCase {
     qpm3 = qpm2.subMap.get( "b" );
     assertTrue( qpm3.terminal );
     assertEquals( 1F, qpm3.boost, 0);
-    
+
     // phraseHighlight = false, fieldMatch = true
     fq = new FieldQuery( query, false, true );
     map = fq.rootMaps;
@@ -415,7 +415,7 @@ public class FieldQueryTest extends AbstractTestCase {
     qpm2 = qpm.subMap.get( "b" );
     assertTrue( qpm2.terminal );
     assertEquals( 1F, qpm2.boost, 0);
-    
+
     // phraseHighlight = false, fieldMatch = false
     fq = new FieldQuery( query, false, false );
     map = fq.rootMaps;
@@ -452,10 +452,10 @@ public class FieldQueryTest extends AbstractTestCase {
     qpm2 = qpm.subMap.get( "b" );
     assertEquals( 2F, qpm2.boost, 0);
   }
-  
+
   public void testQueryPhraseMap1PhraseAnother() throws Exception {
     Query query = pqF( "search", "engines" );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query, true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -473,12 +473,12 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm3.terminal );
     assertEquals( 1F, qpm3.boost, 0);
   }
-  
+
   public void testQueryPhraseMap2Phrases() throws Exception {
     BooleanQuery.Builder query = new BooleanQuery.Builder();
     query.add( pqF( "a", "b" ), Occur.SHOULD );
     query.add( pqF( 2, "c", "d" ), Occur.SHOULD );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query.build(), true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -508,12 +508,12 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm3.terminal );
     assertEquals( 2F, qpm3.boost, 0);
   }
-  
+
   public void testQueryPhraseMap2PhrasesFields() throws Exception {
     BooleanQuery.Builder query = new BooleanQuery.Builder();
     query.add( pq( F1, "a", "b" ), Occur.SHOULD );
     query.add( pq( 2F, F2, "c", "d" ), Occur.SHOULD );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query.build(), true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -545,7 +545,7 @@ public class FieldQueryTest extends AbstractTestCase {
     qpm3 = qpm2.subMap.get( "d" );
     assertTrue( qpm3.terminal );
     assertEquals( 2F, qpm3.boost, 0);
-    
+
     // phraseHighlight = true, fieldMatch = false
     fq = new FieldQuery( query.build(), true, false );
     map = fq.rootMaps;
@@ -576,10 +576,10 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm3.terminal );
     assertEquals( 2F, qpm3.boost, 0);
   }
-  
+
   /*
    * <t>...terminal
-   * 
+   *
    * a-b-c-<t>
    *     +-d-<t>
    * b-c-d-<t>
@@ -590,7 +590,7 @@ public class FieldQueryTest extends AbstractTestCase {
     query.add( pqF( "a", "b", "c" ), Occur.SHOULD );
     query.add( pqF( 2, "b", "c", "d" ), Occur.SHOULD );
     query.add( pqF( 3, "b", "d" ), Occur.SHOULD );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query.build(), true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -636,10 +636,10 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm3.terminal );
     assertEquals( 3F, qpm3.boost, 0);
   }
-  
+
   /*
    * <t>...terminal
-   * 
+   *
    * a-b-<t>
    *   +-c-<t>
    */
@@ -647,7 +647,7 @@ public class FieldQueryTest extends AbstractTestCase {
     BooleanQuery.Builder query = new BooleanQuery.Builder();
     query.add( pqF( "a", "b" ), Occur.SHOULD );
     query.add( pqF( 2, "a", "b", "c" ), Occur.SHOULD );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query.build(), true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -674,10 +674,10 @@ public class FieldQueryTest extends AbstractTestCase {
     assertTrue( qpm4.terminal );
     assertEquals( 2F, qpm4.boost, 0);
   }
-  
+
   /*
    * <t>...terminal
-   * 
+   *
    * a-a-a-<t>
    *     +-a-<t>
    *       +-a-<t>
@@ -687,7 +687,7 @@ public class FieldQueryTest extends AbstractTestCase {
     BooleanQuery.Builder query = new BooleanQuery.Builder();
     query.add( pqF( "a", "a", "a", "a" ), Occur.SHOULD );
     query.add( pqF( 2, "a", "a", "a" ), Occur.SHOULD );
-    
+
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query.build(), true, true );
     Map<String, QueryPhraseMap> map = fq.rootMaps;
@@ -728,7 +728,7 @@ public class FieldQueryTest extends AbstractTestCase {
     QueryPhraseMap qpm7 = qpm6.subMap.get( "a" );
     assertTrue( qpm7.terminal );
   }
-  
+
   public void testQueryPhraseMapOverlap2gram() throws Exception {
     BooleanQuery.Builder query = new BooleanQuery.Builder();
     query.add(toPhraseQuery(analyze("abc", F, analyzerB), F), Occur.MUST);
@@ -769,7 +769,7 @@ public class FieldQueryTest extends AbstractTestCase {
     qpm3 = qpm2.subMap.get( "cd" );
     assertTrue( qpm3.terminal );
     assertEquals( 1F, qpm3.boost, 0);
-    
+
     // phraseHighlight = false, fieldMatch = true
     fq = new FieldQuery( query.build(), false, true );
     map = fq.rootMaps;
@@ -815,13 +815,13 @@ public class FieldQueryTest extends AbstractTestCase {
     assertEquals( 1F, qpm2.boost, 0);
     assertEquals( 0, qpm2.subMap.size() );
   }
-  
+
   public void testSearchPhrase() throws Exception {
     Query query = pqF( "a", "b", "c" );
 
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query, true, true );
-    
+
     // "a"
     List<TermInfo> phraseCandidate = new ArrayList<>();
     phraseCandidate.add( new TermInfo( "a", 0, 1, 0, 1 ) );
@@ -836,14 +836,14 @@ public class FieldQueryTest extends AbstractTestCase {
 
     // phraseHighlight = true, fieldMatch = false
     fq = new FieldQuery( query, true, false );
-    
+
     // "a b c"
     assertNotNull( fq.searchPhrase( F, phraseCandidate ) );
     assertNotNull( fq.searchPhrase( "x", phraseCandidate ) );
 
     // phraseHighlight = false, fieldMatch = true
     fq = new FieldQuery( query, false, true );
-    
+
     // "a"
     phraseCandidate.clear();
     phraseCandidate.add( new TermInfo( "a", 0, 1, 0, 1 ) );
@@ -856,14 +856,14 @@ public class FieldQueryTest extends AbstractTestCase {
     assertNotNull( fq.searchPhrase( F, phraseCandidate ) );
     assertNull( fq.searchPhrase( "x", phraseCandidate ) );
   }
-  
+
   public void testSearchPhraseSlop() throws Exception {
     // "a b c"~0
     Query query = pqF( "a", "b", "c" );
 
     // phraseHighlight = true, fieldMatch = true
     FieldQuery fq = new FieldQuery( query, true, true );
-    
+
     // "a b c" w/ position-gap = 2
     List<TermInfo> phraseCandidate = new ArrayList<>();
     phraseCandidate.add( new TermInfo( "a", 0, 1, 0, 1 ) );
@@ -876,10 +876,10 @@ public class FieldQueryTest extends AbstractTestCase {
 
     // phraseHighlight = true, fieldMatch = true
     fq = new FieldQuery( query, true, true );
-    
+
     // "a b c" w/ position-gap = 2
     assertNotNull( fq.searchPhrase( F, phraseCandidate ) );
-    
+
     // "a b c" w/ position-gap = 3
     phraseCandidate.clear();
     phraseCandidate.add( new TermInfo( "a", 0, 1, 0, 1 ) );
@@ -887,7 +887,7 @@ public class FieldQueryTest extends AbstractTestCase {
     phraseCandidate.add( new TermInfo( "c", 4, 5, 6, 1 ) );
     assertNull( fq.searchPhrase( F, phraseCandidate ) );
   }
-  
+
   public void testHighlightQuery() throws Exception {
     makeIndexStrMV();
     defgMultiTermQueryTest(new WildcardQuery(new Term(F, "d*g")));
@@ -897,7 +897,7 @@ public class FieldQueryTest extends AbstractTestCase {
     makeIndexStrMV();
     defgMultiTermQueryTest(new PrefixQuery(new Term(F, "de")));
   }
-  
+
   public void testRegexpQuery() throws Exception {
     makeIndexStrMV();
     Term term = new Term(F, "d[a-z].g");
@@ -918,7 +918,7 @@ public class FieldQueryTest extends AbstractTestCase {
     phraseCandidate.add( new TermInfo( "defg", 0, 12, 0, 1 ) );
     assertNotNull (fq.searchPhrase(F, phraseCandidate));
   }
-  
+
   public void testStopRewrite() throws Exception {
     Query q = new Query() {
 
@@ -926,13 +926,21 @@ public class FieldQueryTest extends AbstractTestCase {
       public String toString(String field) {
         return "DummyQuery";
       }
-      
+      @Override
+      public boolean equals(Object o) {
+        throw new AssertionError();
+      }
+
+      @Override
+      public int hashCode() {
+        throw new AssertionError();
+      }
     };
     make1d1fIndex( "a" );
     assertNotNull(reader);
     new FieldQuery(q, reader, true, true );
   }
-  
+
   public void testFlattenConstantScoreQuery() throws Exception {
     initBoost();
     Query query = new ConstantScoreQuery(pqF( "A" ));
@@ -942,5 +950,5 @@ public class FieldQueryTest extends AbstractTestCase {
     fq.flatten( query, reader, flatQueries, 1f );
     assertCollectionQueries( flatQueries, tq( boost, "A" ) );
   }
-  
+
 }

lucene/join/src/java/org/apache/lucene/search/join/GlobalOrdinalsQuery.java

@@ -65,24 +65,21 @@ final class GlobalOrdinalsQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-    if (!super.equals(o)) return false;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
 
-    GlobalOrdinalsQuery that = (GlobalOrdinalsQuery) o;
-
-    if (!fromQuery.equals(that.fromQuery)) return false;
-    if (!joinField.equals(that.joinField)) return false;
-    if (!toQuery.equals(that.toQuery)) return false;
-    if (!indexReader.equals(that.indexReader)) return false;
-
-    return true;
+  private boolean equalsTo(GlobalOrdinalsQuery other) {
+    return fromQuery.equals(other.fromQuery) &&
+           joinField.equals(other.joinField) &&
+           toQuery.equals(other.toQuery) &&
+           indexReader.equals(other.indexReader);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result = 31 * result + joinField.hashCode();
     result = 31 * result + toQuery.hashCode();
     result = 31 * result + fromQuery.hashCode();

lucene/join/src/java/org/apache/lucene/search/join/GlobalOrdinalsWithScoreQuery.java

@@ -66,26 +66,23 @@ final class GlobalOrdinalsWithScoreQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-    if (!super.equals(o)) return false;
-
-    GlobalOrdinalsWithScoreQuery that = (GlobalOrdinalsWithScoreQuery) o;
-
-    if (min != that.min) return false;
-    if (max != that.max) return false;
-    if (!joinField.equals(that.joinField)) return false;
-    if (!fromQuery.equals(that.fromQuery)) return false;
-    if (!toQuery.equals(that.toQuery)) return false;
-    if (!indexReader.equals(that.indexReader)) return false;
-
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(GlobalOrdinalsWithScoreQuery other) {
+    return min == other.min &&
+           max == other.max &&
+           joinField.equals(other.joinField) &&
+           fromQuery.equals(other.fromQuery) &&
+           toQuery.equals(other.toQuery) &&
+           indexReader.equals(other.indexReader);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result = 31 * result + joinField.hashCode();
     result = 31 * result + toQuery.hashCode();
     result = 31 * result + fromQuery.hashCode();

lucene/join/src/java/org/apache/lucene/search/join/PointInSetIncludingScoreQuery.java

@@ -6,7 +6,6 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.function.BiFunction;
-import java.util.function.Function;
 
 import org.apache.lucene.document.DoublePoint;
 import org.apache.lucene.document.FloatPoint;
@@ -21,7 +20,6 @@ import org.apache.lucene.index.PointValues.Relation;
 import org.apache.lucene.index.PrefixCodedTerms;
 import org.apache.lucene.index.PrefixCodedTerms.TermIterator;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.ConstantScoreScorer;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.IndexSearcher;
@@ -32,7 +30,6 @@ import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.BitSetIterator;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.DocIdSetBuilder;
 import org.apache.lucene.util.FixedBitSet;
 
 /*
@@ -289,7 +286,7 @@ abstract class PointInSetIncludingScoreQuery extends Query {
 
   @Override
   public final int hashCode() {
-    int hash = super.hashCode();
+    int hash = classHash();
     hash = 31 * hash + field.hashCode();
     hash = 31 * hash + originalQuery.hashCode();
     hash = 31 * hash + sortedPackedPointsHashCode;
@@ -299,16 +296,16 @@ abstract class PointInSetIncludingScoreQuery extends Query {
 
   @Override
   public final boolean equals(Object other) {
-    if (super.equals(other)) {
-      final PointInSetIncludingScoreQuery q = (PointInSetIncludingScoreQuery) other;
-      return q.field.equals(field) &&
-        q.originalQuery.equals(originalQuery) &&
-        q.bytesPerDim == bytesPerDim &&
-        q.sortedPackedPointsHashCode == sortedPackedPointsHashCode &&
-        q.sortedPackedPoints.equals(sortedPackedPoints);
-    }
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
 
-    return false;
+  private boolean equalsTo(PointInSetIncludingScoreQuery other) {
+    return other.field.equals(field) &&
+           other.originalQuery.equals(originalQuery) &&
+           other.bytesPerDim == bytesPerDim &&
+           other.sortedPackedPointsHashCode == sortedPackedPointsHashCode &&
+           other.sortedPackedPoints.equals(sortedPackedPoints);
   }
 
   @Override

lucene/join/src/java/org/apache/lucene/search/join/TermsIncludingScoreQuery.java

@@ -86,29 +86,20 @@ class TermsIncludingScoreQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) {
-      return true;
-    } if (!super.equals(obj)) {
-      return false;
-    } if (getClass() != obj.getClass()) {
-      return false;
-    }
-
-    TermsIncludingScoreQuery other = (TermsIncludingScoreQuery) obj;
-    if (!field.equals(other.field)) {
-      return false;
-    }
-    if (!unwrittenOriginalQuery.equals(other.unwrittenOriginalQuery)) {
-      return false;
-    }
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(TermsIncludingScoreQuery other) {
+    return field.equals(other.field) &&
+           unwrittenOriginalQuery.equals(other.unwrittenOriginalQuery);
   }
 
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = super.hashCode();
+    int result = classHash();
     result += prime * field.hashCode();
     result += prime * unwrittenOriginalQuery.hashCode();
     return result;

lucene/join/src/java/org/apache/lucene/search/join/ToChildBlockJoinQuery.java

@@ -344,21 +344,20 @@ public class ToChildBlockJoinQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object _other) {
-    if (_other instanceof ToChildBlockJoinQuery) {
-      final ToChildBlockJoinQuery other = (ToChildBlockJoinQuery) _other;
-      return origParentQuery.equals(other.origParentQuery) &&
-        parentsFilter.equals(other.parentsFilter) &&
-        super.equals(other);
-    } else {
-      return false;
-    }
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(ToChildBlockJoinQuery other) {
+    return origParentQuery.equals(other.origParentQuery) &&
+           parentsFilter.equals(other.parentsFilter);
   }
 
   @Override
   public int hashCode() {
     final int prime = 31;
-    int hash = super.hashCode();
+    int hash = classHash();
     hash = prime * hash + origParentQuery.hashCode();
     hash = prime * hash + parentsFilter.hashCode();
     return hash;

lucene/join/src/java/org/apache/lucene/search/join/ToParentBlockJoinQuery.java

@@ -474,22 +474,21 @@ public class ToParentBlockJoinQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object _other) {
-    if (_other instanceof ToParentBlockJoinQuery) {
-      final ToParentBlockJoinQuery other = (ToParentBlockJoinQuery) _other;
-      return origChildQuery.equals(other.origChildQuery) &&
-        parentsFilter.equals(other.parentsFilter) &&
-        scoreMode == other.scoreMode && 
-        super.equals(other);
-    } else {
-      return false;
-    }
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(ToParentBlockJoinQuery other) {
+    return origChildQuery.equals(other.origChildQuery) &&
+           parentsFilter.equals(other.parentsFilter) &&
+           scoreMode == other.scoreMode;
   }
 
   @Override
   public int hashCode() {
     final int prime = 31;
-    int hash = super.hashCode();
+    int hash = classHash();
     hash = prime * hash + origChildQuery.hashCode();
     hash = prime * hash + scoreMode.hashCode();
     hash = prime * hash + parentsFilter.hashCode();

lucene/join/src/test/org/apache/lucene/search/join/TestBlockJoin.java

@@ -152,7 +152,7 @@ public class TestBlockJoin extends LuceneTestCase {
     docs.add(makeResume("Frank", "United States"));
     w.addDocuments(docs);
     w.commit();
-    
+
     IndexReader r = DirectoryReader.open(w);
     w.close();
     IndexSearcher s = new IndexSearcher(r);
@@ -184,7 +184,7 @@ public class TestBlockJoin extends LuceneTestCase {
     r.close();
     dir.close();
   }
-  
+
 
   public void testSimple() throws Exception {
 
@@ -203,7 +203,7 @@ public class TestBlockJoin extends LuceneTestCase {
     docs.add(makeJob("java", 2006));
     docs.add(makeResume("Frank", "United States"));
     w.addDocuments(docs);
-    
+
     IndexReader r = w.getReader();
     w.close();
     IndexSearcher s = newSearcher(r, false);
@@ -232,7 +232,7 @@ public class TestBlockJoin extends LuceneTestCase {
     ToParentBlockJoinCollector c = new ToParentBlockJoinCollector(Sort.RELEVANCE, 1, true, true);
 
     s.search(fullQuery.build(), c);
-    
+
     TopGroups<Integer> results = c.getTopGroups(childJoinQuery, null, 0, 10, 0, true);
     assertFalse(Float.isNaN(results.maxScore));
 
@@ -259,7 +259,7 @@ public class TestBlockJoin extends LuceneTestCase {
     BooleanQuery.Builder fullChildQuery = new BooleanQuery.Builder();
     fullChildQuery.add(new BooleanClause(parentJoinQuery, Occur.MUST));
     fullChildQuery.add(new BooleanClause(childQuery.build(), Occur.MUST));
-    
+
     //System.out.println("FULL: " + fullChildQuery);
     TopDocs hits = s.search(fullChildQuery.build(), 10);
     assertEquals(1, hits.totalHits);
@@ -272,7 +272,7 @@ public class TestBlockJoin extends LuceneTestCase {
     // Test with filter on child docs:
     fullChildQuery.add(new TermQuery(new Term("skill", "foosball")), Occur.FILTER);
     assertEquals(0, s.search(fullChildQuery.build(), 1).totalHits);
-    
+
     r.close();
     dir.close();
   }
@@ -296,7 +296,7 @@ public class TestBlockJoin extends LuceneTestCase {
     IndexSearcher s = newSearcher(r, false);
 
     // Hacky: this causes the query to need 2 rewrite
-    // iterations: 
+    // iterations:
     BooleanQuery.Builder builder = new BooleanQuery.Builder();
     builder.add(IntPoint.newExactQuery("year", 2007), BooleanClause.Occur.MUST);
     Query qc = new Query() {
@@ -309,6 +309,16 @@ public class TestBlockJoin extends LuceneTestCase {
       public String toString(String field) {
         return "hack!";
       }
+
+      @Override
+      public boolean equals(Object o) {
+        return o == this;
+      }
+
+      @Override
+      public int hashCode() {
+        return System.identityHashCode(this);
+      }
     };
 
     BitSetProducer parentsFilter = new QueryBitSetProducer(new TermQuery(new Term("docType", "resume")));
@@ -353,15 +363,15 @@ public class TestBlockJoin extends LuceneTestCase {
     docs2.add(makeJob("java", 2006));
     Collections.shuffle(docs2, random());
     docs2.add(makeResume("Frank", "United States"));
-    
+
     addSkillless(w);
     boolean turn = random().nextBoolean();
     w.addDocuments(turn ? docs:docs2);
 
     addSkillless(w);
-    
+
     w.addDocuments(!turn ? docs:docs2);
-    
+
     addSkillless(w);
 
     IndexReader r = w.getReader();
@@ -379,11 +389,11 @@ public class TestBlockJoin extends LuceneTestCase {
 
     // Define parent document criteria (find a resident in the UK)
     Query parentQuery = new TermQuery(new Term("country", "United Kingdom"));
-      
+
     // Wrap the child document query to 'join' any matches
     // up to corresponding parent:
     ToParentBlockJoinQuery childJoinQuery = new ToParentBlockJoinQuery(childQuery.build(), parentsFilter, ScoreMode.Avg);
-      
+
     assertEquals("no filter - both passed", 2, s.search(childJoinQuery, 10).totalHits);
 
     Query query = new BooleanQuery.Builder()
@@ -396,14 +406,14 @@ public class TestBlockJoin extends LuceneTestCase {
         .add(new TermQuery(new Term("docType", "resume")), Occur.FILTER)
         .build();
     assertEquals("dummy filter passes everyone ", 2, s.search(query, 10).totalHits);
-      
+
     // not found test
     query = new BooleanQuery.Builder()
         .add(childJoinQuery, Occur.MUST)
         .add(new TermQuery(new Term("country", "Oz")), Occur.FILTER)
         .build();
     assertEquals("noone live there", 0, s.search(query, 1).totalHits);
-      
+
     // apply the UK filter by the searcher
     query = new BooleanQuery.Builder()
         .add(childJoinQuery, Occur.MUST)
@@ -421,11 +431,11 @@ public class TestBlockJoin extends LuceneTestCase {
     TopDocs usThen = s.search(query, 1);
     assertEquals("has filter - single passed", 1, usThen.totalHits);
     assertEquals("Frank", r.document(usThen.scoreDocs[0].doc).get("name"));
-    
-    
+
+
     TermQuery us = new TermQuery(new Term("country", "United States"));
-    assertEquals("@ US we have java and ruby", 2, 
-        s.search(new ToChildBlockJoinQuery(us, 
+    assertEquals("@ US we have java and ruby", 2,
+        s.search(new ToChildBlockJoinQuery(us,
                           parentsFilter), 10).totalHits );
 
     query = new BooleanQuery.Builder()
@@ -452,7 +462,7 @@ public class TestBlockJoin extends LuceneTestCase {
       w.addDocument(makeResume("Skillless", random().nextBoolean() ? "United Kingdom":"United States"));
     }
   }
-  
+
   private Document getParentDoc(IndexReader reader, BitSetProducer parents, int childDocID) throws IOException {
     final List<LeafReaderContext> leaves = reader.leaves();
     final int subIndex = ReaderUtil.subIndex(childDocID, leaves);
@@ -460,14 +470,14 @@ public class TestBlockJoin extends LuceneTestCase {
     final BitSet bits = parents.getBitSet(leaf);
     return leaf.reader().document(bits.nextSetBit(childDocID - leaf.docBase));
   }
-  
+
   public void testBoostBug() throws Exception {
     final Directory dir = newDirectory();
     final RandomIndexWriter w = new RandomIndexWriter(random(), dir);
     IndexReader r = w.getReader();
     w.close();
     IndexSearcher s = newSearcher(r);
-    
+
     ToParentBlockJoinQuery q = new ToParentBlockJoinQuery(new MatchNoDocsQuery(), new QueryBitSetProducer(new MatchAllDocsQuery()), ScoreMode.Avg);
     QueryUtils.check(random(), q, s);
     s.search(q, 10);
@@ -489,7 +499,7 @@ public class TestBlockJoin extends LuceneTestCase {
       } else {
         valueCount = TestUtil.nextInt(random(), 1, maxUniqueValues);
       }
-        
+
       final String[] values = fields[fieldID] = new String[valueCount];
       for(int i=0;i<valueCount;i++) {
         values[i] = TestUtil.randomRealisticUnicodeString(random());
@@ -711,7 +721,7 @@ public class TestBlockJoin extends LuceneTestCase {
         childQuery = bq.build();
       } else {
         BooleanQuery.Builder bq = new BooleanQuery.Builder();
-        
+
         bq.add(new TermQuery(randomChildTerm(childFields[0])),
                BooleanClause.Occur.MUST);
         final int childFieldID = TestUtil.nextInt(random(), 1, childFields.length - 1);
@@ -894,7 +904,7 @@ public class TestBlockJoin extends LuceneTestCase {
         parentQuery2 = bq.build();
       } else {
         BooleanQuery.Builder bq = new BooleanQuery.Builder();
-        
+
         bq.add(new TermQuery(randomParentTerm(parentFields[0])),
                BooleanClause.Occur.MUST);
         final int fieldID = TestUtil.nextInt(random(), 1, parentFields.length - 1);
@@ -943,7 +953,7 @@ public class TestBlockJoin extends LuceneTestCase {
           }
           childJoinQuery2 = bq.build();
         }
-        
+
         if (random().nextBoolean()) { // filtered case
           childQuery2 = parentQuery2;
           childQuery2 = new BooleanQuery.Builder()
@@ -966,7 +976,7 @@ public class TestBlockJoin extends LuceneTestCase {
       }
 
       final Sort childSort2 = getRandomSort("child", childFields.length);
-              
+
       // Search denormalized index:
       if (VERBOSE) {
         System.out.println("TEST: run top down query=" + childQuery2 + " sort=" + childSort2);
@@ -1334,7 +1344,7 @@ public class TestBlockJoin extends LuceneTestCase {
     // parent last:
     docs.add(parent);
     w.addDocuments(docs);
-    
+
     IndexReader r = w.getReader();
     w.close();
 
@@ -1398,17 +1408,17 @@ public class TestBlockJoin extends LuceneTestCase {
     parent.add(newStringField("isParent", "yes", Field.Store.NO));
     parent.add(new StoredField("parentID", "1"));
     parent.add(new SortedDocValuesField("parentID", new BytesRef("1")));
-    
+
 
     // parent last:
     docs.add(parent);
     w.addDocuments(docs);
-    
+
     IndexReader r = w.getReader();
     w.close();
 
     IndexSearcher searcher = new ToParentBlockJoinIndexSearcher(r);
-    
+
     // never matches:
     Query childQuery = new TermQuery(new Term("childText", "bogus"));
     BitSetProducer parentsFilter = new QueryBitSetProducer(new TermQuery(new Term("isParent", "yes")));
@@ -1471,7 +1481,7 @@ public class TestBlockJoin extends LuceneTestCase {
     // parent last:
     docs.add(parent);
     w.addDocuments(docs);
-    
+
     IndexReader r = w.getReader();
     w.close();
 
@@ -1536,7 +1546,7 @@ public class TestBlockJoin extends LuceneTestCase {
     ToChildBlockJoinQuery parentJoinQuery = new ToChildBlockJoinQuery(parentQuery, parentsFilter);
     TopDocs topdocs = s.search(parentJoinQuery, 3);
     assertEquals(1, topdocs.totalHits);
-    
+
     r.close();
     dir.close();
   }
@@ -1583,7 +1593,7 @@ public class TestBlockJoin extends LuceneTestCase {
     w.close();
     dir.close();
   }
-  
+
   //LUCENE-6588
   // delete documents to simulate FilteredQuery applying a filter as acceptDocs
   public void testParentScoringBug() throws Exception {
@@ -1610,20 +1620,20 @@ public class TestBlockJoin extends LuceneTestCase {
     // Create a filter that defines "parent" documents in the index - in this case resumes
     BitSetProducer parentsFilter = new QueryBitSetProducer(new TermQuery(new Term("docType", "resume")));
     Query parentQuery = new PrefixQuery(new Term("country", "United"));
-    
+
     ToChildBlockJoinQuery toChildQuery = new ToChildBlockJoinQuery(parentQuery, parentsFilter);
-    
+
     TopDocs hits = s.search(toChildQuery, 10);
     assertEquals(hits.scoreDocs.length, 2);
     for (int i = 0; i < hits.scoreDocs.length; i++) {
       if (hits.scoreDocs[i].score == 0.0)
         fail("Failed to calculate score for hit #"+i);
     }
-    
+
     r.close();
     dir.close();
   }
-  
+
   public void testToChildBlockJoinQueryExplain() throws Exception {
     final Directory dir = newDirectory();
     final RandomIndexWriter w = new RandomIndexWriter(random(), dir);
@@ -1648,21 +1658,21 @@ public class TestBlockJoin extends LuceneTestCase {
     // Create a filter that defines "parent" documents in the index - in this case resumes
     BitSetProducer parentsFilter = new QueryBitSetProducer(new TermQuery(new Term("docType", "resume")));
     Query parentQuery = new PrefixQuery(new Term("country", "United"));
-    
+
     ToChildBlockJoinQuery toChildQuery = new ToChildBlockJoinQuery(parentQuery, parentsFilter);
-    
+
     TopDocs hits = s.search(toChildQuery, 10);
     assertEquals(hits.scoreDocs.length, 2);
     for (int i = 0; i < hits.scoreDocs.length; i++) {
       assertEquals(hits.scoreDocs[i].score, s.explain(toChildQuery, hits.scoreDocs[i].doc).getValue(), 0.01);
     }
-    
+
     r.close();
     dir.close();
   }
-  
+
   public void testToChildInitialAdvanceParentButNoKids() throws Exception {
-    
+
     final Directory dir = newDirectory();
     final RandomIndexWriter w = new RandomIndexWriter(random(), dir);
 
@@ -1689,13 +1699,13 @@ public class TestBlockJoin extends LuceneTestCase {
     final int firstKid = nextDocScorer.iterator().nextDoc();
     assertTrue("firstKid not found", DocIdSetIterator.NO_MORE_DOCS != firstKid);
     assertEquals(firstKid, advancingScorer.iterator().advance(0));
-    
+
     r.close();
     dir.close();
   }
 
   public void testMultiChildQueriesOfDiffParentLevels() throws Exception {
-    
+
     final Directory dir = newDirectory();
     final RandomIndexWriter w = new RandomIndexWriter(random(), dir);
 
@@ -1703,7 +1713,7 @@ public class TestBlockJoin extends LuceneTestCase {
     final int numResumes = atLeast(100);
     for (int r = 0; r < numResumes; r++) {
       final List<Document> docs = new ArrayList<>();
-      
+
       final int rv = TestUtil.nextInt(random(), 1, 10);
       final int numJobs = atLeast(10);
       for (int j = 0; j < numJobs; j++) {
@@ -1732,19 +1742,19 @@ public class TestBlockJoin extends LuceneTestCase {
     for (int i = 0; i < numQueryIters; i++) {
       final int qjv = TestUtil.nextInt(random(), -10, -1);
       final int qrv = TestUtil.nextInt(random(), 1, 10);
-      
+
       Query resumeQuery = new ToChildBlockJoinQuery(new TermQuery(new Term("country","rv" + qrv)),
                                                     resumeFilter);
-      
+
       Query jobQuery = new ToChildBlockJoinQuery(IntPoint.newRangeQuery("year", qjv, qjv),
                                                  jobFilter);
-      
+
       BooleanQuery.Builder fullQuery = new BooleanQuery.Builder();
       fullQuery.add(new BooleanClause(jobQuery, Occur.MUST));
       fullQuery.add(new BooleanClause(resumeQuery, Occur.MUST));
-      
+
       TopDocs hits = s.search(fullQuery.build(), 100); // NOTE: totally possible that we'll get no matches
-      
+
       for (ScoreDoc sd : hits.scoreDocs) {
         // since we're looking for children of jobs, all results must be qualifications
         String q = r.document(sd.doc).get("qualification");
@@ -1753,10 +1763,10 @@ public class TestBlockJoin extends LuceneTestCase {
         assertTrue(q + " MUST contain rv" + qrv, q.contains("rv"+qrv));
       }
     }
-    
+
     r.close();
     dir.close();
   }
 
-  
+
 }

lucene/join/src/test/org/apache/lucene/search/join/TestJoinUtil.java

@@ -507,6 +507,17 @@ public class TestJoinUtil extends LuceneTestCase {
       public String toString(String field) {
         return fieldQuery.toString(field);
       }
+
+      @Override
+      public boolean equals(Object o) {
+        return o == this;
+      }
+
+      @Override
+      public int hashCode() {
+        return System.identityHashCode(this);
+      }
+
     };
 
     Directory dir = newDirectory();
@@ -964,10 +975,10 @@ public class TestJoinUtil extends LuceneTestCase {
 
         final Query joinQuery;
         {
-          // single val can be handled by multiple-vals 
+          // single val can be handled by multiple-vals
           final boolean muliValsQuery = multipleValuesPerDocument || random().nextBoolean();
-          final String fromField = from ? "from":"to"; 
-          final String toField = from ? "to":"from"; 
+          final String fromField = from ? "from":"to";
+          final String toField = from ? "to":"from";
 
           int surpriseMe = random().nextInt(3);
           switch (surpriseMe) {
@@ -1079,22 +1090,22 @@ public class TestJoinUtil extends LuceneTestCase {
     for (int i = 0; i < numRandomValues; i++) {
       String uniqueRandomValue;
       do {
-        // the trick is to generate values which will be ordered similarly for string, ints&longs, positive nums makes it easier 
+        // the trick is to generate values which will be ordered similarly for string, ints&longs, positive nums makes it easier
         final int nextInt = random.nextInt(Integer.MAX_VALUE);
         uniqueRandomValue = String.format(Locale.ROOT, "%08x", nextInt);
         assert nextInt == Integer.parseUnsignedInt(uniqueRandomValue,16);
       } while ("".equals(uniqueRandomValue) || trackSet.contains(uniqueRandomValue));
-     
+
       // Generate unique values and empty strings aren't allowed.
       trackSet.add(uniqueRandomValue);
-      
+
       context.randomFrom[i] = random.nextBoolean();
       context.randomUniqueValues[i] = uniqueRandomValue;
-      
+
     }
 
     List<String> randomUniqueValuesReplica = new ArrayList<>(Arrays.asList(context.randomUniqueValues));
-        
+
     RandomDoc[] docs = new RandomDoc[nDocs];
     for (int i = 0; i < nDocs; i++) {
       String id = Integer.toString(i);
@@ -1117,7 +1128,7 @@ public class TestJoinUtil extends LuceneTestCase {
       Collections.shuffle(subValues, random);
       }
       for (String linkValue : subValues) {
-        
+
         assert !docs[i].linkValues.contains(linkValue);
         docs[i].linkValues.add(linkValue);
         if (from) {
@@ -1131,7 +1142,7 @@ public class TestJoinUtil extends LuceneTestCase {
           context.fromDocuments.get(linkValue).add(docs[i]);
           context.randomValueFromDocs.get(value).add(docs[i]);
           addLinkFields(random, document,  "from", linkValue, multipleValuesPerDocument, globalOrdinalJoin);
-          
+
         } else {
           if (!context.toDocuments.containsKey(linkValue)) {
             context.toDocuments.put(linkValue, new ArrayList<>());

lucene/misc/src/test/org/apache/lucene/uninverting/TestFieldCacheSortRandom.java

@@ -296,19 +296,22 @@ public class TestFieldCacheSortRandom extends LuceneTestCase {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      RandomQuery other = (RandomQuery) obj;
-      return seed == other.seed && docValues == other.docValues;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(RandomQuery other) {
+      return seed == other.seed && 
+             docValues == other.docValues &&
+             density == other.density;
     }
 
     @Override
     public int hashCode() {
-      int h = Objects.hash(seed, density);
+      int h = classHash();
+      h = 31 * h + Objects.hash(seed, density);
       h = 31 * h + System.identityHashCode(docValues);
-      h = 31 * h + super.hashCode();
       return h;
     }
   }

lucene/queries/src/java/org/apache/lucene/queries/BoostingQuery.java

@@ -134,11 +134,6 @@ public class BoostingQuery extends Query {
       };
     }
 
-    @Override
-    public int hashCode() {
-      return 31 * super.hashCode() + Objects.hash(match, context, boost);
-    }
-
     public Query getMatch() {
       return match;
     }
@@ -152,14 +147,20 @@ public class BoostingQuery extends Query {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      BoostingQuery that = (BoostingQuery) obj;
-      return match.equals(that.match)
-          && context.equals(that.context)
-          && Float.floatToIntBits(boost) == Float.floatToIntBits(that.boost);
+    public int hashCode() {
+      return 31 * classHash() + Objects.hash(match, context, boost);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(BoostingQuery other) {
+      return match.equals(other.match)
+          && context.equals(other.context)
+          && Float.floatToIntBits(boost) == Float.floatToIntBits(other.boost);
     }
 
     @Override

lucene/queries/src/java/org/apache/lucene/queries/CommonTermsQuery.java

@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.IndexReader;
@@ -411,42 +412,35 @@ public class CommonTermsQuery extends Query {
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = super.hashCode();
+    int result = classHash();
     result = prime * result + (disableCoord ? 1231 : 1237);
     result = prime * result + Float.floatToIntBits(highFreqBoost);
-    result = prime * result
-        + ((highFreqOccur == null) ? 0 : highFreqOccur.hashCode());
+    result = prime * result + Objects.hashCode(highFreqOccur);
+    result = prime * result + Objects.hashCode(lowFreqOccur);
     result = prime * result + Float.floatToIntBits(lowFreqBoost);
-    result = prime * result
-        + ((lowFreqOccur == null) ? 0 : lowFreqOccur.hashCode());
     result = prime * result + Float.floatToIntBits(maxTermFrequency);
     result = prime * result + Float.floatToIntBits(lowFreqMinNrShouldMatch);
     result = prime * result + Float.floatToIntBits(highFreqMinNrShouldMatch);
-    result = prime * result + ((terms == null) ? 0 : terms.hashCode());
+    result = prime * result + Objects.hashCode(terms);
     return result;
   }
-  
+
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    CommonTermsQuery other = (CommonTermsQuery) obj;
-    if (disableCoord != other.disableCoord) return false;
-    if (Float.floatToIntBits(highFreqBoost) != Float
-        .floatToIntBits(other.highFreqBoost)) return false;
-    if (highFreqOccur != other.highFreqOccur) return false;
-    if (Float.floatToIntBits(lowFreqBoost) != Float
-        .floatToIntBits(other.lowFreqBoost)) return false;
-    if (lowFreqOccur != other.lowFreqOccur) return false;
-    if (Float.floatToIntBits(maxTermFrequency) != Float
-        .floatToIntBits(other.maxTermFrequency)) return false;
-    if (lowFreqMinNrShouldMatch != other.lowFreqMinNrShouldMatch) return false;
-    if (highFreqMinNrShouldMatch != other.highFreqMinNrShouldMatch) return false;
-    if (terms == null) {
-      if (other.terms != null) return false;
-    } else if (!terms.equals(other.terms)) return false;
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(CommonTermsQuery other) {
+    return disableCoord == other.disableCoord &&
+           Float.floatToIntBits(highFreqBoost) == Float.floatToIntBits(other.highFreqBoost) &&
+           highFreqOccur == other.highFreqOccur &&
+           lowFreqOccur == other.lowFreqOccur &&
+           Float.floatToIntBits(lowFreqBoost) == Float.floatToIntBits(other.lowFreqBoost) &&
+           Float.floatToIntBits(maxTermFrequency) == Float.floatToIntBits(other.maxTermFrequency) &&
+           lowFreqMinNrShouldMatch == other.lowFreqMinNrShouldMatch &&
+           highFreqMinNrShouldMatch == other.highFreqMinNrShouldMatch &&
+           terms.equals(other.terms);
   }
 
   /**

lucene/queries/src/java/org/apache/lucene/queries/CustomScoreQuery.java

@@ -137,25 +137,25 @@ public class CustomScoreQuery extends Query implements Cloneable {
 
   /** Returns true if <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (this == o)
-      return true;
-    if (!super.equals(o))
-      return false;
-    CustomScoreQuery other = (CustomScoreQuery)o;
-    if (!this.subQuery.equals(other.subQuery) ||
-        this.strict != other.strict ||
-        this.scoringQueries.length != other.scoringQueries.length) {
-      return false;
-    }
-    return Arrays.equals(scoringQueries, other.scoringQueries);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(CustomScoreQuery other) {
+    return subQuery.equals(other.subQuery) &&
+           strict == other.strict &&
+           scoringQueries.length == other.scoringQueries.length &&
+           Arrays.equals(scoringQueries, other.scoringQueries);
   }
 
   /** Returns a hash code value for this object. */
   @Override
   public int hashCode() {
-    return (getClass().hashCode() + subQuery.hashCode() + Arrays.hashCode(scoringQueries))
-      ^ (strict ? 1234 : 4321);
+    // Didn't change this hashcode, but it looks suspicious.
+    return (classHash() + 
+        subQuery.hashCode() + 
+        Arrays.hashCode(scoringQueries)) ^ (strict ? 1234 : 4321);
   }
   
   /**

lucene/queries/src/java/org/apache/lucene/queries/TermsQuery.java

@@ -173,22 +173,20 @@ public class TermsQuery extends Query implements Accountable {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) {
-      return true;
-    }
-    if (!super.equals(obj)) {
-      return false;
-    }
-    TermsQuery that = (TermsQuery) obj;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(TermsQuery other) {
     // termData might be heavy to compare so check the hash code first
-    return termDataHashCode == that.termDataHashCode
-        && termData.equals(that.termData);
+    return termDataHashCode == other.termDataHashCode && 
+           termData.equals(other.termData);
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + termDataHashCode;
+    return 31 * classHash() + termDataHashCode;
   }
 
   /** Returns the terms wrapped in a PrefixCodedTerms. */

lucene/queries/src/java/org/apache/lucene/queries/function/BoostedQuery.java

@@ -160,16 +160,19 @@ public final class BoostedQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-  if (!super.equals(o)) return false;
-    BoostedQuery other = (BoostedQuery)o;
-    return this.q.equals(other.q)
-           && this.boostVal.equals(other.boostVal);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(BoostedQuery other) {
+    return q.equals(other.q) &&
+           boostVal.equals(other.boostVal);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
+    int h = classHash();
     h = 31 * h + q.hashCode();
     h = 31 * h + boostVal.hashCode();
     return h;

lucene/queries/src/java/org/apache/lucene/queries/function/FunctionQuery.java

@@ -163,15 +163,13 @@ public class FunctionQuery extends Query {
 
   /** Returns true if <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (!FunctionQuery.class.isInstance(o)) return false;
-    FunctionQuery other = (FunctionQuery)o;
-    return super.equals(o)
-            && this.func.equals(other.func);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           func.equals(((FunctionQuery) other).func);
   }
 
   @Override
   public int hashCode() {
-    return super.hashCode() ^ func.hashCode();
+    return classHash() ^ func.hashCode();
   }
 }

lucene/queries/src/java/org/apache/lucene/queries/function/FunctionRangeQuery.java

@@ -95,21 +95,22 @@ public class FunctionRangeQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (!(o instanceof FunctionRangeQuery)) return false;
-    if (!super.equals(o)) return false;
-    FunctionRangeQuery that = (FunctionRangeQuery) o;
-    return Objects.equals(includeLower, that.includeLower) &&
-        Objects.equals(includeUpper, that.includeUpper) &&
-        Objects.equals(valueSource, that.valueSource) &&
-        Objects.equals(lowerVal, that.lowerVal) &&
-        Objects.equals(upperVal, that.upperVal);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(FunctionRangeQuery other) {
+    return Objects.equals(includeLower, other.includeLower) &&
+           Objects.equals(includeUpper, other.includeUpper) &&
+           Objects.equals(valueSource, other.valueSource) &&
+           Objects.equals(lowerVal, other.lowerVal) &&
+           Objects.equals(upperVal, other.upperVal);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(super.hashCode(), valueSource, lowerVal, upperVal, includeLower, includeUpper);
+    return classHash() ^ Objects.hash(valueSource, lowerVal, upperVal, includeLower, includeUpper);
   }
 
   @Override

lucene/queries/src/java/org/apache/lucene/queries/mlt/MoreLikeThisQuery.java

@@ -26,6 +26,7 @@ import java.io.IOException;
 import java.io.StringReader;
 import java.util.Arrays;
 import java.util.Set;
+import java.util.Objects;
 
 /**
  * A simple wrapper for MoreLikeThis for use in scenarios where a Query object is required eg
@@ -48,10 +49,10 @@ public class MoreLikeThisQuery extends Query {
    * @param moreLikeFields fields used for similarity measure
    */
   public MoreLikeThisQuery(String likeText, String[] moreLikeFields, Analyzer analyzer, String fieldName) {
-    this.likeText = likeText;
-    this.moreLikeFields = moreLikeFields;
-    this.analyzer = analyzer;
-    this.fieldName = fieldName;
+    this.likeText = Objects.requireNonNull(likeText);
+    this.moreLikeFields = Objects.requireNonNull(moreLikeFields);
+    this.analyzer = Objects.requireNonNull(analyzer);
+    this.fieldName = Objects.requireNonNull(fieldName);
   }
 
   @Override
@@ -152,43 +153,31 @@ public class MoreLikeThisQuery extends Query {
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = super.hashCode();
-    result = prime * result + ((analyzer == null) ? 0 : analyzer.hashCode());
-    result = prime * result + ((fieldName == null) ? 0 : fieldName.hashCode());
-    result = prime * result + ((likeText == null) ? 0 : likeText.hashCode());
+    int result = classHash();
+    result = prime * result + Objects.hash(analyzer, fieldName, likeText, stopWords);
     result = prime * result + maxQueryTerms;
     result = prime * result + minDocFreq;
     result = prime * result + minTermFrequency;
     result = prime * result + Arrays.hashCode(moreLikeFields);
     result = prime * result + Float.floatToIntBits(percentTermsToMatch);
-    result = prime * result + ((stopWords == null) ? 0 : stopWords.hashCode());
     return result;
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    MoreLikeThisQuery other = (MoreLikeThisQuery) obj;
-    if (analyzer == null) {
-      if (other.analyzer != null) return false;
-    } else if (!analyzer.equals(other.analyzer)) return false;
-    if (fieldName == null) {
-      if (other.fieldName != null) return false;
-    } else if (!fieldName.equals(other.fieldName)) return false;
-    if (likeText == null) {
-      if (other.likeText != null) return false;
-    } else if (!likeText.equals(other.likeText)) return false;
-    if (maxQueryTerms != other.maxQueryTerms) return false;
-    if (minDocFreq != other.minDocFreq) return false;
-    if (minTermFrequency != other.minTermFrequency) return false;
-    if (!Arrays.equals(moreLikeFields, other.moreLikeFields)) return false;
-    if (Float.floatToIntBits(percentTermsToMatch) != Float
-        .floatToIntBits(other.percentTermsToMatch)) return false;
-    if (stopWords == null) {
-      if (other.stopWords != null) return false;
-    } else if (!stopWords.equals(other.stopWords)) return false;
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(MoreLikeThisQuery other) {
+    return maxQueryTerms == other.maxQueryTerms &&
+           minDocFreq == other.minDocFreq &&
+           minTermFrequency == other.minTermFrequency &&
+           Float.floatToIntBits(percentTermsToMatch) == Float.floatToIntBits(other.percentTermsToMatch) &&
+           analyzer.equals(other.analyzer) &&
+           fieldName.equals(other.fieldName) &&
+           likeText.equals(other.likeText) &&
+           Arrays.equals(moreLikeFields, other.moreLikeFields) &&
+           Objects.equals(stopWords, other.stopWords);
   }
 }

lucene/queries/src/java/org/apache/lucene/queries/payloads/PayloadScoreQuery.java

@@ -19,6 +19,7 @@ package org.apache.lucene.queries.payloads;
 import java.io.IOException;
 import java.util.Map;
 import java.util.Set;
+import java.util.Objects;
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.PostingsEnum;
@@ -60,8 +61,8 @@ public class PayloadScoreQuery extends SpanQuery {
    * @param includeSpanScore include both span score and payload score in the scoring algorithm
    */
   public PayloadScoreQuery(SpanQuery wrappedQuery, PayloadFunction function, boolean includeSpanScore) {
-    this.wrappedQuery = wrappedQuery;
-    this.function = function;
+    this.wrappedQuery = Objects.requireNonNull(wrappedQuery);
+    this.function = Objects.requireNonNull(function);
     this.includeSpanScore = includeSpanScore;
   }
 
@@ -93,23 +94,21 @@ public class PayloadScoreQuery extends SpanQuery {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (!(o instanceof PayloadScoreQuery)) return false;
-    if (!super.equals(o)) return false;
-
-    PayloadScoreQuery that = (PayloadScoreQuery) o;
-
-    if (wrappedQuery != null ? !wrappedQuery.equals(that.wrappedQuery) : that.wrappedQuery != null) return false;
-    return !(function != null ? !function.equals(that.function) : that.function != null);
-
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(PayloadScoreQuery other) {
+    return wrappedQuery.equals(other.wrappedQuery) && 
+           function.equals(other.function);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
-    result = 31 * result + (wrappedQuery != null ? wrappedQuery.hashCode() : 0);
-    result = 31 * result + (function != null ? function.hashCode() : 0);
+    int result = classHash();
+    result = 31 * result + Objects.hashCode(wrappedQuery);
+    result = 31 * result + Objects.hashCode(function);
     return result;
   }
 

lucene/queries/src/java/org/apache/lucene/queries/payloads/SpanPayloadCheckQuery.java

@@ -173,18 +173,13 @@ public class SpanPayloadCheckQuery extends SpanQuery {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (! super.equals(o)) {
-      return false;
-    }
-    SpanPayloadCheckQuery other = (SpanPayloadCheckQuery)o;
-    return this.payloadToMatch.equals(other.payloadToMatch);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           payloadToMatch.equals(((SpanPayloadCheckQuery) other).payloadToMatch);
   }
 
   @Override
   public int hashCode() {
-    int h = super.hashCode();
-    h = (h * 63) ^ payloadToMatch.hashCode();
-    return h;
+    return classHash() ^ payloadToMatch.hashCode();
   }
 }

lucene/queryparser/src/java/org/apache/lucene/queryparser/complexPhrase/ComplexPhraseQueryParser.java

@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Objects;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.index.IndexReader;
@@ -221,9 +222,8 @@ public class ComplexPhraseQueryParser extends QueryParser {
 
     public ComplexPhraseQuery(String field, String phrasedQueryStringContents,
         int slopFactor, boolean inOrder) {
-      super();
-      this.field = field;
-      this.phrasedQueryStringContents = phrasedQueryStringContents;
+      this.field = Objects.requireNonNull(field);
+      this.phrasedQueryStringContents = Objects.requireNonNull(phrasedQueryStringContents);
       this.slopFactor = slopFactor;
       this.inOrder = inOrder;
     }
@@ -407,43 +407,25 @@ public class ComplexPhraseQueryParser extends QueryParser {
     @Override
     public int hashCode() {
       final int prime = 31;
-      int result = super.hashCode();
-      result = prime * result + ((field == null) ? 0 : field.hashCode());
-      result = prime
-          * result
-          + ((phrasedQueryStringContents == null) ? 0
-              : phrasedQueryStringContents.hashCode());
+      int result = classHash();
+      result = prime * result + field.hashCode();
+      result = prime * result + phrasedQueryStringContents.hashCode();
       result = prime * result + slopFactor;
       result = prime * result + (inOrder ? 1 : 0);
       return result;
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (this == obj)
-        return true;
-      if (obj == null)
-        return false;
-      if (getClass() != obj.getClass())
-        return false;
-      if (!super.equals(obj)) {
-        return false;
-      }
-      ComplexPhraseQuery other = (ComplexPhraseQuery) obj;
-      if (field == null) {
-        if (other.field != null)
-          return false;
-      } else if (!field.equals(other.field))
-        return false;
-      if (phrasedQueryStringContents == null) {
-        if (other.phrasedQueryStringContents != null)
-          return false;
-      } else if (!phrasedQueryStringContents
-          .equals(other.phrasedQueryStringContents))
-        return false;
-      if (slopFactor != other.slopFactor)
-        return false;
-      return inOrder == other.inOrder;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(ComplexPhraseQuery other) {
+      return field.equals(other.field) &&
+             phrasedQueryStringContents.equals(other.phrasedQueryStringContents) &&
+             slopFactor == other.slopFactor &&
+             inOrder == other.inOrder;
     }
   }
 }

lucene/queryparser/src/java/org/apache/lucene/queryparser/surround/query/RewriteQuery.java

@@ -16,6 +16,7 @@
  */
 package org.apache.lucene.queryparser.surround.query;
 import java.io.IOException;
+import java.util.Objects;
 
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.Query;
@@ -29,9 +30,9 @@ abstract class RewriteQuery<SQ extends SrndQuery> extends Query {
       SQ srndQuery,
       String fieldName,
       BasicQueryFactory qf) {
-    this.srndQuery = srndQuery;
-    this.fieldName = fieldName;
-    this.qf = qf;
+    this.srndQuery = Objects.requireNonNull(srndQuery);
+    this.fieldName = Objects.requireNonNull(fieldName);
+    this.qf = Objects.requireNonNull(qf);
   }
 
   @Override
@@ -49,24 +50,22 @@ abstract class RewriteQuery<SQ extends SrndQuery> extends Query {
 
   @Override
   public int hashCode() {
-    return super.hashCode()
-    ^ fieldName.hashCode()
-    ^ qf.hashCode()
-    ^ srndQuery.hashCode();
+    return classHash()
+      ^ fieldName.hashCode()
+      ^ qf.hashCode()
+      ^ srndQuery.hashCode();
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (obj == null)
-      return false;
-    if (! getClass().equals(obj.getClass()))
-      return false;
-    @SuppressWarnings("unchecked") RewriteQuery<SQ> other = (RewriteQuery<SQ>)obj;
-    return super.equals(obj)
-      && fieldName.equals(other.fieldName)
-      && qf.equals(other.qf)
-      && srndQuery.equals(other.srndQuery);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
   }
 
+  private boolean equalsTo(RewriteQuery<?> other) {
+    return fieldName.equals(other.fieldName) && 
+           qf.equals(other.qf) && 
+           srndQuery.equals(other.srndQuery);
+  }
 }
 

lucene/queryparser/src/test/org/apache/lucene/queryparser/classic/TestMultiAnalyzer.java

@@ -18,6 +18,7 @@ package org.apache.lucene.queryparser.classic;
 
 import java.io.IOException;
 import java.io.Reader;
+import java.util.Objects;
 
 import org.apache.lucene.analysis.*;
 import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
@@ -38,7 +39,7 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
   private static int multiToken = 0;
 
   public void testMultiAnalyzer() throws ParseException {
-    
+
     QueryParser qp = new QueryParser("", new MultiAnalyzer());
 
     // trivial, no multiple tokens:
@@ -91,7 +92,7 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
     assertEquals("+Synonym(multi multi2) +foo", qp.parse("multi foo").toString());
 
   }
-    
+
   public void testMultiAnalyzerWithSubclassOfQueryParser() throws ParseException {
 
     DumbQueryParser qp = new DumbQueryParser("", new MultiAnalyzer());
@@ -104,22 +105,22 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
     assertEquals("\"(multi multi2) bar\"~99",
                  qp.getSuperFieldQuery("","multi bar", true).toString());
 
-    
+
     // ask sublcass to parse phrase with modified default slop
     assertEquals("\"(multi multi2) foo\"~99 bar",
                  qp.parse("\"multi foo\" bar").toString());
-    
+
   }
-    
+
   public void testPosIncrementAnalyzer() throws ParseException {
     QueryParser qp = new QueryParser("", new PosIncrementAnalyzer());
     assertEquals("quick brown", qp.parse("the quick brown").toString());
     assertEquals("quick brown fox", qp.parse("the quick brown fox").toString());
   }
-  
+
   /**
    * Expands "multi" to "multi" and "multi2", both at the same position,
-   * and expands "triplemulti" to "triplemulti", "multi3", and "multi2".  
+   * and expands "triplemulti" to "triplemulti", "multi3", and "multi2".
    */
   private class MultiAnalyzer extends Analyzer {
 
@@ -131,16 +132,16 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
   }
 
   private final class TestFilter extends TokenFilter {
-    
+
     private String prevType;
     private int prevStartOffset;
     private int prevEndOffset;
-    
+
     private final CharTermAttribute termAtt;
     private final PositionIncrementAttribute posIncrAtt;
     private final OffsetAttribute offsetAtt;
     private final TypeAttribute typeAtt;
-    
+
     public TestFilter(TokenStream in) {
       super(in);
       termAtt = addAttribute(CharTermAttribute.class);
@@ -202,10 +203,10 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
   }
 
   private final class TestPosIncrementFilter extends TokenFilter {
-    
+
     CharTermAttribute termAtt;
     PositionIncrementAttribute posIncrAtt;
-    
+
     public TestPosIncrementFilter(TokenStream in) {
       super(in);
       termAtt = addAttribute(CharTermAttribute.class);
@@ -231,13 +232,13 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
 
     /** a very simple subclass of QueryParser */
     private final static class DumbQueryParser extends QueryParser {
-        
+
         public DumbQueryParser(String f, Analyzer a) {
             super(f, a);
         }
 
         /** expose super's version */
-        public Query getSuperFieldQuery(String f, String t, boolean quoted) 
+        public Query getSuperFieldQuery(String f, String t, boolean quoted)
             throws ParseException {
             return super.getFieldQuery(f,t,quoted);
         }
@@ -248,22 +249,32 @@ public class TestMultiAnalyzer extends BaseTokenStreamTestCase {
             return new DumbQueryWrapper(getSuperFieldQuery(f,t,quoted));
         }
     }
-    
+
     /**
      * A very simple wrapper to prevent instanceof checks but uses
      * the toString of the query it wraps.
      */
     private final static class DumbQueryWrapper extends Query {
-
         private Query q;
+
         public DumbQueryWrapper(Query q) {
-            super();
-            this.q = q;
+            this.q = Objects.requireNonNull(q);
         }
         @Override
         public String toString(String f) {
             return q.toString(f);
         }
+
+        @Override
+        public boolean equals(Object other) {
+            return sameClassAs(other) &&
+                   Objects.equals(q, ((DumbQueryWrapper) other).q);
+        }
+
+        @Override
+        public int hashCode() {
+            return classHash() & q.hashCode();
+        }
     }
-    
+
 }

lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointBoxQuery.java

@@ -215,7 +215,7 @@ abstract class LatLonPointBoxQuery extends Query {
 
   @Override
   public final int hashCode() {
-    int hash = super.hashCode();
+    int hash = classHash();
     hash = 31 * hash + field.hashCode();
     hash = 31 * hash + Arrays.hashCode(lowerPoint);
     hash = 31 * hash + Arrays.hashCode(upperPoint);
@@ -226,32 +226,16 @@ abstract class LatLonPointBoxQuery extends Query {
 
   @Override
   public final boolean equals(Object other) {
-    if (super.equals(other) == false) {
-      return false;
-    }
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
 
-    final LatLonPointBoxQuery q = (LatLonPointBoxQuery) other;
-    if (field.equals(q.field) == false) {
-      return false;
-    }
-
-    if (q.numDims != numDims) {
-      return false;
-    }
-
-    if (q.bytesPerDim != bytesPerDim) {
-      return false;
-    }
-
-    if (Arrays.equals(lowerPoint, q.lowerPoint) == false) {
-      return false;
-    }
-    
-    if (Arrays.equals(upperPoint, q.upperPoint) == false) {
-      return false;
-    }
-
-    return true;
+  private boolean equalsTo(LatLonPointBoxQuery other) {
+    return field.equals(other.field) &&
+           numDims == other.numDims &&
+           bytesPerDim == other.bytesPerDim &&
+           Arrays.equals(lowerPoint, other.lowerPoint) &&
+           Arrays.equals(upperPoint, other.upperPoint);
   }
 
   @Override

lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointDistanceQuery.java

@@ -263,7 +263,7 @@ final class LatLonPointDistanceQuery extends Query {
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = super.hashCode();
+    int result = classHash();
     result = prime * result + field.hashCode();
     long temp;
     temp = Double.doubleToLongBits(latitude);
@@ -276,16 +276,16 @@ final class LatLonPointDistanceQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    LatLonPointDistanceQuery other = (LatLonPointDistanceQuery) obj;
-    if (field.equals(other.field) == false) return false;
-    if (Double.doubleToLongBits(latitude) != Double.doubleToLongBits(other.latitude)) return false;
-    if (Double.doubleToLongBits(longitude) != Double.doubleToLongBits(other.longitude)) return false;
-    if (Double.doubleToLongBits(radiusMeters) != Double.doubleToLongBits(other.radiusMeters)) return false;
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(LatLonPointDistanceQuery other) {
+    return field.equals(other.field) &&
+           Double.doubleToLongBits(latitude) == Double.doubleToLongBits(other.latitude) &&
+           Double.doubleToLongBits(longitude) == Double.doubleToLongBits(other.longitude) &&
+           Double.doubleToLongBits(radiusMeters) == Double.doubleToLongBits(other.radiusMeters);
   }
 
   @Override

lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointInPolygonQuery.java

@@ -169,21 +169,21 @@ final class LatLonPointInPolygonQuery extends Query {
   @Override
   public int hashCode() {
     final int prime = 31;
-    int result = super.hashCode();
+    int result = classHash();
     result = prime * result + field.hashCode();
     result = prime * result + Arrays.hashCode(polygons);
     return result;
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    LatLonPointInPolygonQuery other = (LatLonPointInPolygonQuery) obj;
-    if (!field.equals(other.field)) return false;
-    if (!Arrays.equals(polygons, other.polygons)) return false;
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(LatLonPointInPolygonQuery other) {
+    return field.equals(other.field) &&
+           Arrays.equals(polygons, other.polygons);
   }
 
   @Override

lucene/sandbox/src/java/org/apache/lucene/sandbox/queries/FuzzyLikeThisQuery.java

@@ -21,6 +21,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.Objects;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.TokenStream;
@@ -77,45 +78,27 @@ public class FuzzyLikeThisQuery extends Query
 
     @Override
     public int hashCode() {
-      final int prime = 31;
-      int result = super.hashCode();
-      result = prime * result + ((analyzer == null) ? 0 : analyzer.hashCode());
-      result = prime * result
-          + ((fieldVals == null) ? 0 : fieldVals.hashCode());
+      int prime = 31;
+      int result = classHash();
+      result = prime * result + Objects.hashCode(analyzer);
+      result = prime * result + Objects.hashCode(fieldVals);
       result = prime * result + (ignoreTF ? 1231 : 1237);
       result = prime * result + maxNumTerms;
       return result;
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (this == obj)
-        return true;
-      if (obj == null)
-        return false;
-      if (getClass() != obj.getClass())
-        return false;
-      if (!super.equals(obj)) {
-        return false;
-      }
-      FuzzyLikeThisQuery other = (FuzzyLikeThisQuery) obj;
-      if (analyzer == null) {
-        if (other.analyzer != null)
-          return false;
-      } else if (!analyzer.equals(other.analyzer))
-        return false;
-      if (fieldVals == null) {
-        if (other.fieldVals != null)
-          return false;
-      } else if (!fieldVals.equals(other.fieldVals))
-        return false;
-      if (ignoreTF != other.ignoreTF)
-        return false;
-      if (maxNumTerms != other.maxNumTerms)
-        return false;
-      return true;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
     }
 
+    private boolean equalsTo(FuzzyLikeThisQuery other) {
+      return Objects.equals(analyzer, other.analyzer) &&
+             Objects.equals(fieldVals, other.fieldVals) &&
+             ignoreTF == other.ignoreTF &&
+             maxNumTerms == other.maxNumTerms;
+    }
 
     /**
      * 

lucene/sandbox/src/java/org/apache/lucene/search/DocValuesNumbersQuery.java

@@ -58,21 +58,19 @@ public class DocValuesNumbersQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (!super.equals(obj)) {
-      return false;
-    }
-    // super.equals ensures we are the same class:
-    DocValuesNumbersQuery that = (DocValuesNumbersQuery) obj;
-    if (!field.equals(that.field)) {
-      return false;
-    }
-    return numbers.equals(that.numbers);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(DocValuesNumbersQuery other) {
+    return field.equals(other.field) &&
+           numbers.equals(other.numbers);
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + Objects.hash(field, numbers);
+    return 31 * classHash() + Objects.hash(field, numbers);
   }
 
   public String getField() {

lucene/sandbox/src/java/org/apache/lucene/search/DocValuesRangeQuery.java

@@ -78,22 +78,22 @@ public final class DocValuesRangeQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    final DocValuesRangeQuery that = (DocValuesRangeQuery) obj;
-    return field.equals(that.field)
-        && Objects.equals(lowerVal, that.lowerVal)
-        && Objects.equals(upperVal, that.upperVal)
-        && includeLower == that.includeLower
-        && includeUpper == that.includeUpper
-        && super.equals(obj);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(DocValuesRangeQuery other) {
+    return field.equals(other.field) && 
+           Objects.equals(lowerVal, other.lowerVal) && 
+           Objects.equals(upperVal, other.upperVal) && 
+           includeLower == other.includeLower && 
+           includeUpper == other.includeUpper;
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + Objects.hash(field, lowerVal, upperVal, includeLower, includeUpper);
+    return 31 * classHash() + Objects.hash(field, lowerVal, upperVal, includeLower, includeUpper);
   }
 
   public String getField() {

lucene/sandbox/src/java/org/apache/lucene/search/DocValuesTermsQuery.java

@@ -119,20 +119,19 @@ public class DocValuesTermsQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    DocValuesTermsQuery that = (DocValuesTermsQuery) obj;
-    if (!field.equals(that.field)) {
-      return false;
-    }
-    return Arrays.equals(terms, that.terms);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private boolean equalsTo(DocValuesTermsQuery other) {
+    return field.equals(other.field) &&
+           Arrays.equals(terms, other.terms);
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + Objects.hash(field, Arrays.asList(terms));
+    return 31 * classHash() + Objects.hash(field, Arrays.asList(terms));
   }
 
   @Override

lucene/sandbox/src/java/org/apache/lucene/search/TermAutomatonQuery.java

@@ -232,33 +232,32 @@ public class TermAutomatonQuery extends Query {
 
   /** Returns true iff <code>o</code> is equal to this. */
   @Override
-  public boolean equals(Object o) {
-    if (!(o instanceof TermAutomatonQuery)) {
-      return false;
-    }
-    TermAutomatonQuery other = (TermAutomatonQuery) o;
-
-    if (det == null) {
-      throw new IllegalStateException("please call finish first");
-    }
-    if (other.det == null) {
-      throw new IllegalStateException("please call other.finish first");
-    }
-
-    // NOTE: not quite correct, because if terms were added in different
-    // order in each query but the language is the same, we return false:
-    return super.equals(o)
-      && this.termToID.equals(other.termToID) &&
-      Operations.sameLanguage(det, other.det);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+
+  private static boolean checkFinished(TermAutomatonQuery q) {
+    if (q.det == null) {
+      throw new IllegalStateException("Call finish first on: " + q);
+    }
+    return true;
+  }
+
+  private boolean equalsTo(TermAutomatonQuery other) {
+    // NOTE: not quite correct, because if terms were added in different
+    // order in each query but the language is the same, we return false:
+    return checkFinished(this) &&
+           checkFinished(other) &&
+           termToID.equals(other.termToID) &&
+           Operations.sameLanguage(det, other.det);
   }
 
-  /** Returns a hash code value for this object.  This is very costly! */
   @Override
   public int hashCode() {
-    if (det == null) {
-      throw new IllegalStateException("please call finish first");
-    }
-    return super.hashCode() ^ termToID.hashCode() + det.toDot().hashCode();
+    checkFinished(this);
+    // TODO: LUCENE-7295: Automaton.toDot() is very costly!
+    return classHash() ^ termToID.hashCode() + det.toDot().hashCode();
   }
 
   /** Returns the dot (graphviz) representation of this automaton.

lucene/sandbox/src/test/org/apache/lucene/search/TestTermAutomatonQuery.java

@@ -45,9 +45,7 @@ import org.apache.lucene.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.BitDocIdSet;
 import org.apache.lucene.util.BitSetIterator;
-import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
 import org.apache.lucene.util.IOUtils;
@@ -659,17 +657,19 @@ public class TestTermAutomatonQuery extends LuceneTestCase {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (super.equals(obj) == false) {
-        return false;
-      }
-      RandomQuery other = (RandomQuery) obj;
-      return seed == other.seed && density == other.density;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
+
+    private boolean equalsTo(RandomQuery other) {
+      return seed == other.seed &&  
+             density == other.density;
     }
 
     @Override
     public int hashCode() {
-      return Objects.hash(super.hashCode(), seed, density);
+      return classHash() ^ Objects.hash(seed, density);
     }
   }
 

lucene/spatial-extras/src/java/org/apache/lucene/spatial/composite/CompositeVerifyQuery.java

@@ -57,22 +57,19 @@ public class CompositeVerifyQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-    if (!super.equals(o)) return false;
-
-    CompositeVerifyQuery that = (CompositeVerifyQuery) o;
-
-    if (!indexQuery.equals(that.indexQuery)) return false;
-    if (!predicateValueSource.equals(that.predicateValueSource)) return false;
-
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(CompositeVerifyQuery other) {
+    return indexQuery.equals(other.indexQuery) &&
+           predicateValueSource.equals(other.predicateValueSource);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result = 31 * result + indexQuery.hashCode();
     result = 31 * result + predicateValueSource.hashCode();
     return result;

lucene/spatial-extras/src/java/org/apache/lucene/spatial/composite/IntersectsRPTVerifyQuery.java

@@ -63,20 +63,19 @@ public class IntersectsRPTVerifyQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (!super.equals(o)) return false;
-
-    IntersectsRPTVerifyQuery that = (IntersectsRPTVerifyQuery) o;
-
-    if (!intersectsDiffQuery.equals(that.intersectsDiffQuery)) return false;
-    return predicateValueSource.equals(that.predicateValueSource);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
 
+  private boolean equalsTo(IntersectsRPTVerifyQuery other) {
+    return intersectsDiffQuery.equals(other.intersectsDiffQuery) &&
+           predicateValueSource.equals(other.predicateValueSource);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result = 31 * result + intersectsDiffQuery.hashCode();
     result = 31 * result + predicateValueSource.hashCode();
     return result;

lucene/spatial-extras/src/java/org/apache/lucene/spatial/prefix/AbstractPrefixTreeQuery.java

@@ -56,21 +56,19 @@ public abstract class AbstractPrefixTreeQuery extends Query {
 
   @Override
   public boolean equals(Object o) {
-    if (this == o) return true;
-    if (super.equals(o) == false) return false;
+    return sameClassAs(o) &&
+           equalsTo(getClass().cast(o));
+  }
 
-    AbstractPrefixTreeQuery that = (AbstractPrefixTreeQuery) o;
-
-    if (detailLevel != that.detailLevel) return false;
-    if (!fieldName.equals(that.fieldName)) return false;
-    if (!queryShape.equals(that.queryShape)) return false;
-
-    return true;
+  private boolean equalsTo(AbstractPrefixTreeQuery other) {
+    return detailLevel == other.detailLevel &&
+           fieldName.equals(other.fieldName) &&
+           queryShape.equals(other.queryShape);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result = 31 * result + queryShape.hashCode();
     result = 31 * result + fieldName.hashCode();
     result = 31 * result + detailLevel;

lucene/spatial-extras/src/java/org/apache/lucene/spatial/serialized/SerializedDVStrategy.java

@@ -156,20 +156,14 @@ public class SerializedDVStrategy extends SpatialStrategy {
     }
 
     @Override
-    public boolean equals(Object o) {
-      if (this == o) return true;
-      if (super.equals(o) == false) return false;
-
-      PredicateValueSourceQuery that = (PredicateValueSourceQuery) o;
-
-      if (!predicateValueSource.equals(that.predicateValueSource)) return false;
-
-      return true;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             predicateValueSource.equals(((PredicateValueSourceQuery) other).predicateValueSource);
     }
 
     @Override
     public int hashCode() {
-      return super.hashCode() + 31 * predicateValueSource.hashCode();
+      return classHash() + 31 * predicateValueSource.hashCode();
     }
 
     @Override

lucene/spatial/src/java/org/apache/lucene/spatial/geopoint/search/GeoPointInBBoxQuery.java

@@ -132,25 +132,22 @@ public class GeoPointInBBoxQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (!(o instanceof GeoPointInBBoxQuery)) return false;
-    if (!super.equals(o)) return false;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
 
-    GeoPointInBBoxQuery that = (GeoPointInBBoxQuery) o;
-
-    if (Double.compare(that.minLat, minLat) != 0) return false;
-    if (Double.compare(that.maxLat, maxLat) != 0) return false;
-    if (Double.compare(that.minLon, minLon) != 0) return false;
-    if (Double.compare(that.maxLon, maxLon) != 0) return false;
-    if (!field.equals(that.field)) return false;
-
-    return true;
+  private boolean equalsTo(GeoPointInBBoxQuery other) {
+    return Double.compare(other.minLat, minLat) == 0 &&
+           Double.compare(other.maxLat, maxLat) == 0 &&
+           Double.compare(other.minLon, minLon) == 0 &&
+           Double.compare(other.maxLon, maxLon) == 0 &&
+           field.equals(other.field);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     long temp;
     result = 31 * result + field.hashCode();
     temp = Double.doubleToLongBits(minLat);

lucene/spatial/src/java/org/apache/lucene/spatial/geopoint/search/GeoPointTermQueryConstantScoreWrapper.java

@@ -64,17 +64,14 @@ final class GeoPointTermQueryConstantScoreWrapper <Q extends GeoPointMultiTermQu
   }
 
   @Override
-  public final boolean equals(final Object o) {
-    if (super.equals(o) == false) {
-      return false;
-    }
-    final GeoPointTermQueryConstantScoreWrapper<?> that = (GeoPointTermQueryConstantScoreWrapper<?>) o;
-    return this.query.equals(that.query);
+  public final boolean equals(final Object other) {
+    return sameClassAs(other) &&
+           query.equals(((GeoPointTermQueryConstantScoreWrapper<?>) other).query);
   }
 
   @Override
   public final int hashCode() {
-    return 31 * super.hashCode() + query.hashCode();
+    return 31 * classHash() + query.hashCode();
   }
 
   @Override

lucene/spatial3d/src/java/org/apache/lucene/spatial3d/PointInGeo3DShapeQuery.java

@@ -43,14 +43,14 @@ final class PointInGeo3DShapeQuery extends Query {
   final String field;
   final GeoShape shape;
   final XYZBounds shapeBounds;
-  
+
   /** The lats/lons must be clockwise or counter-clockwise. */
   public PointInGeo3DShapeQuery(String field, GeoShape shape) {
     this.field = field;
     this.shape = shape;
     this.shapeBounds = new XYZBounds();
     shape.getBounds(shapeBounds);
-    
+
     if (shape instanceof BasePlanetObject) {
       BasePlanetObject planetObject = (BasePlanetObject) shape;
       if (planetObject.getPlanetModel().equals(PlanetModel.WGS84) == false) {
@@ -115,23 +115,19 @@ final class PointInGeo3DShapeQuery extends Query {
   }
 
   @Override
-  @SuppressWarnings({"unchecked","rawtypes"})
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-    if (!super.equals(o)) return false;
-
-    PointInGeo3DShapeQuery that = (PointInGeo3DShapeQuery) o;
-    if (field.equals(that.field) == false) {
-      return false;
-    }
-
-    return shape.equals(that.shape);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           equalsTo(getClass().cast(other));
+  }
+  
+  private boolean equalsTo(PointInGeo3DShapeQuery other) {
+    return field.equals(other.field) &&
+           shape.equals(other.shape);
   }
 
   @Override
   public int hashCode() {
-    int result = super.hashCode();
+    int result = classHash();
     result = 31 * result + field.hashCode();
     result = 31 * result + shape.hashCode();
     return result;

lucene/suggest/src/java/org/apache/lucene/search/suggest/document/ContextQuery.java

@@ -34,7 +34,7 @@ import org.apache.lucene.util.automaton.Operations;
 import org.apache.lucene.util.fst.Util;
 
 /**
- * A {@link CompletionQuery} that match documents specified by
+ * A {@link CompletionQuery} that matches documents specified by
  * a wrapped {@link CompletionQuery} supporting boosting and/or filtering
  * by specified contexts.
  * <p>
@@ -315,4 +315,15 @@ public class ContextQuery extends CompletionQuery {
       return currentBoost + innerWeight.boost();
     }
   }
+
+  @Override
+  public boolean equals(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int hashCode() {
+    throw new UnsupportedOperationException();
+  }
+
 }

lucene/suggest/src/java/org/apache/lucene/search/suggest/document/PrefixCompletionQuery.java

@@ -77,4 +77,14 @@ public class PrefixCompletionQuery extends CompletionQuery {
   public Analyzer getAnalyzer() {
     return analyzer;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int hashCode() {
+    throw new UnsupportedOperationException();
+  }
 }

lucene/suggest/src/java/org/apache/lucene/search/suggest/document/RegexCompletionQuery.java

@@ -106,4 +106,13 @@ public class RegexCompletionQuery extends CompletionQuery {
     return maxDeterminizedStates;
   }
 
+  @Override
+  public boolean equals(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int hashCode() {
+    throw new UnsupportedOperationException();
+  }
 }

lucene/test-framework/src/java/org/apache/lucene/search/AssertingQuery.java

@@ -49,12 +49,9 @@ public final class AssertingQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (obj == null || !(obj instanceof AssertingQuery)) {
-      return false;
-    }
-    final AssertingQuery that = (AssertingQuery) obj;
-    return this.in.equals(that.in);
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           in.equals(((AssertingQuery) other).in);
   }
 
   @Override

lucene/test-framework/src/java/org/apache/lucene/search/QueryUtils.java

@@ -67,9 +67,20 @@ public class QueryUtils {
       public String toString(String field) {
         return "My Whacky Query";
       }
+
+      @Override
+      public boolean equals(Object o) {
+        return o == this;
+      }
+
+      @Override
+      public int hashCode() {
+        return System.identityHashCode(this);
+      }
+
     };
     checkUnequal(q, whacky);
-    
+
     // null test
     assertFalse(q.equals(null));
   }
@@ -87,13 +98,13 @@ public class QueryUtils {
     // happens, please change test to use a different example.
     assertTrue(q1.hashCode() != q2.hashCode());
   }
-  
+
   /** deep check that explanations of a query 'score' correctly */
   public static void checkExplanations (final Query q, final IndexSearcher s) throws IOException {
     CheckHits.checkExplanations(q, null, s, true);
   }
-  
-  /** 
+
+  /**
    * Various query sanity checks on a searcher, some checks are only done for
    * instanceof IndexSearcher.
    *
@@ -124,22 +135,22 @@ public class QueryUtils {
       throw new RuntimeException(e);
     }
   }
-  
+
   /** This is a MultiReader that can be used for randomly wrapping other readers
    * without creating FieldCache insanity.
    * The trick is to use an opaque/fake cache key. */
   public static class FCInvisibleMultiReader extends MultiReader {
     private final Object cacheKey = new Object();
-  
+
     public FCInvisibleMultiReader(IndexReader... readers) throws IOException {
       super(readers);
     }
-    
+
     @Override
     public Object getCoreCacheKey() {
       return cacheKey;
     }
-    
+
     @Override
     public Object getCombinedCoreAndDeletesKey() {
       return cacheKey;
@@ -147,15 +158,15 @@ public class QueryUtils {
   }
 
   /**
-   * Given an IndexSearcher, returns a new IndexSearcher whose IndexReader 
-   * is a MultiReader containing the Reader of the original IndexSearcher, 
-   * as well as several "empty" IndexReaders -- some of which will have 
-   * deleted documents in them.  This new IndexSearcher should 
+   * Given an IndexSearcher, returns a new IndexSearcher whose IndexReader
+   * is a MultiReader containing the Reader of the original IndexSearcher,
+   * as well as several "empty" IndexReaders -- some of which will have
+   * deleted documents in them.  This new IndexSearcher should
    * behave exactly the same as the original IndexSearcher.
    * @param s the searcher to wrap
    * @param edge if negative, s will be the first sub; if 0, s will be in the middle, if positive s will be the last sub
    */
-  public static IndexSearcher wrapUnderlyingReader(Random random, final IndexSearcher s, final int edge) 
+  public static IndexSearcher wrapUnderlyingReader(Random random, final IndexSearcher s, final int edge)
     throws IOException {
 
     IndexReader r = s.getIndexReader();
@@ -179,7 +190,7 @@ public class QueryUtils {
     out.setSimilarity(s.getSimilarity(true));
     return out;
   }
-  
+
   private static IndexReader emptyReader(final int maxDoc) {
     return new LeafReader() {
 
@@ -248,7 +259,7 @@ public class QueryUtils {
       public FieldInfos getFieldInfos() {
         return new FieldInfos(new FieldInfo[0]);
       }
-      
+
       final Bits liveDocs = new Bits.MatchNoBits(maxDoc);
       @Override
       public Bits getLiveDocs() {
@@ -345,7 +356,7 @@ public class QueryUtils {
                 scorer = w.scorer(context);
                 iterator = scorer.iterator();
               }
-              
+
               int op = order[(opidx[0]++) % order.length];
               // System.out.println(op==skip_op ?
               // "skip("+(sdoc[0]+1)+")":"next()");
@@ -453,7 +464,7 @@ public class QueryUtils {
         }
       }
   }
-    
+
   /** check that first skip on just created scorers always goes to the right doc */
   public static void checkFirstSkipTo(final Query q, final IndexSearcher s) throws IOException {
     //System.out.println("checkFirstSkipTo: "+q);
@@ -479,9 +490,9 @@ public class QueryUtils {
             Assert.assertTrue("query collected "+doc+" but advance("+i+") says no more docs!",scorer.iterator().advance(i) != DocIdSetIterator.NO_MORE_DOCS);
             Assert.assertEquals("query collected "+doc+" but advance("+i+") got to "+scorer.docID(),doc,scorer.docID());
             float advanceScore = scorer.score();
-            Assert.assertEquals("unstable advance("+i+") score!",advanceScore,scorer.score(),maxDiff); 
+            Assert.assertEquals("unstable advance("+i+") score!",advanceScore,scorer.score(),maxDiff);
             Assert.assertEquals("query assigned doc "+doc+" a score of <"+score+"> but advance("+i+") has <"+advanceScore+">!",score,advanceScore,maxDiff);
-            
+
             // Hurry things along if they are going slow (eg
             // if you got SimpleText codec this will kick in):
             if (i < doc && System.currentTimeMillis() - startMS > 5) {
@@ -493,7 +504,7 @@ public class QueryUtils {
           throw new RuntimeException(e);
         }
       }
-      
+
       @Override
       public boolean needsScores() {
         return true;
@@ -596,7 +607,7 @@ public class QueryUtils {
           bulkScorer.score(new LeafCollector() {
             @Override
             public void setScorer(Scorer scorer) throws IOException {}
-            
+
             @Override
             public void collect(int doc) throws IOException {
               // no more matches

lucene/test-framework/src/java/org/apache/lucene/search/RandomApproximationQuery.java

@@ -49,20 +49,14 @@ public class RandomApproximationQuery extends Query {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (super.equals(obj) == false) {
-      return false;
-    }
-    final RandomApproximationQuery that = (RandomApproximationQuery) obj;
-    if (this.query.equals(that.query) == false) {
-      return false;
-    }
-    return true;
+  public boolean equals(Object other) {
+    return sameClassAs(other) &&
+           query.equals(((RandomApproximationQuery) other).query);
   }
 
   @Override
   public int hashCode() {
-    return 31 * super.hashCode() + query.hashCode();
+    return 31 * classHash() + query.hashCode();
   }
 
   @Override

lucene/test-framework/src/java/org/apache/lucene/search/spans/AssertingSpanQuery.java

@@ -21,6 +21,7 @@ import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 
 import java.io.IOException;
+import java.util.Objects;
 
 /** Wraps a span query with asserts */
 public class AssertingSpanQuery extends SpanQuery {
@@ -64,22 +65,17 @@ public class AssertingSpanQuery extends SpanQuery {
   }
 
   @Override
-  public int hashCode() {
-    final int prime = 31;
-    int result = super.hashCode();
-    result = prime * result + ((in == null) ? 0 : in.hashCode());
-    return result;
+  public boolean equals(Object o) {
+    return sameClassAs(o) &&
+           equalsTo(getClass().cast(o));
+  }
+
+  private boolean equalsTo(AssertingSpanQuery other) {
+    return Objects.equals(in, other.in);
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (!super.equals(obj)) return false;
-    if (getClass() != obj.getClass()) return false;
-    AssertingSpanQuery other = (AssertingSpanQuery) obj;
-    if (in == null) {
-      if (other.in != null) return false;
-    } else if (!in.equals(other.in)) return false;
-    return true;
+  public int hashCode() {
+    return (in == null) ? 0 : in.hashCode();
   }
 }

solr/core/src/java/org/apache/solr/schema/LatLonType.java

@@ -554,7 +554,7 @@ class SpatialDistanceQuery extends ExtendedQueryBase implements PostFilter {
   /** Returns true if <code>o</code> is equal to this. */
   @Override
   public boolean equals(Object o) {
-    if (!super.equals(o)) return false;
+    if (!sameClassAs(o)) return false;
     SpatialDistanceQuery other = (SpatialDistanceQuery)o;
     return     this.latCenter == other.latCenter
             && this.lonCenter == other.lonCenter
@@ -576,12 +576,11 @@ class SpatialDistanceQuery extends ExtendedQueryBase implements PostFilter {
   @Override
   public int hashCode() {
     // don't bother making the hash expensive - the center latitude + min longitude will be very unique
-    long hash = Double.doubleToLongBits(latCenter);
+    long hash = classHash();
+    hash = hash * 31 + Double.doubleToLongBits(latCenter);
     hash = hash * 31 + Double.doubleToLongBits(lonMin);
-    hash = hash * 31 + (long)super.hashCode();
-    return (int)(hash >> 32 + hash);
+    return (int) (hash >> 32 + hash);
   }
-
 }
 
 

solr/core/src/java/org/apache/solr/search/BitDocSet.java

@@ -18,6 +18,7 @@ package org.apache.solr.search;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Objects;
 
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -266,11 +267,12 @@ public class BitDocSet extends DocSetBase {
 
   @Override
   public Filter getTopFilter() {
-    final FixedBitSet bs = bits;
     // TODO: if cardinality isn't cached, do a quick measure of sparseness
     // and return null from bits() if too sparse.
 
     return new Filter() {
+      final FixedBitSet bs = bits;
+
       @Override
       public DocIdSet getDocIdSet(final LeafReaderContext context, final Bits acceptDocs) {
         LeafReader reader = context.reader();
@@ -355,10 +357,22 @@ public class BitDocSet extends DocSetBase {
 
         }, acceptDocs2);
       }
+
       @Override
       public String toString(String field) {
         return "BitSetDocTopFilter";
       }
+
+      @Override
+      public boolean equals(Object other) {
+        return sameClassAs(other) &&
+               Objects.equals(bs, getClass().cast(other).bs);
+      }
+      
+      @Override
+      public int hashCode() {
+        return classHash() * 31 + bs.hashCode();
+      }
     };
   }
 

solr/core/src/java/org/apache/solr/search/CollapsingQParserPlugin.java

@@ -239,25 +239,25 @@ public class CollapsingQParserPlugin extends QParserPlugin {
       return false;
     }
 
+    // Only a subset of fields in hashCode/equals?
+
     public int hashCode() {
-      int hashCode = super.hashCode();
+      int hashCode = classHash();
       hashCode = 31 * hashCode + collapseField.hashCode();
       hashCode = 31 * hashCode + groupHeadSelector.hashCode();
       hashCode = 31 * hashCode + nullPolicy;
       return hashCode;
     }
 
-    public boolean equals(Object o) {
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
+    }
 
-      if(o instanceof CollapsingPostFilter) {
-        CollapsingPostFilter c = (CollapsingPostFilter)o;
-        if(this.collapseField.equals(c.collapseField) &&
-           this.groupHeadSelector.equals(c.groupHeadSelector) &&
-           this.nullPolicy == c.nullPolicy) {
-          return true;
-        }
-      }
-      return false;
+    private boolean equalsTo(CollapsingPostFilter other) {
+      return collapseField.equals(other.collapseField) &&
+             groupHeadSelector.equals(other.groupHeadSelector) &&
+             nullPolicy == other.nullPolicy;
     }
 
     public int getCost() {

solr/core/src/java/org/apache/solr/search/DocSetBase.java

@@ -17,6 +17,7 @@
 package org.apache.solr.search;
 
 import java.io.IOException;
+import java.util.Objects;
 
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -161,9 +162,9 @@ abstract class DocSetBase implements DocSet {
 
   @Override
   public Filter getTopFilter() {
-    final FixedBitSet bs = getBits();
-
     return new Filter() {
+      final FixedBitSet bs = getBits();
+
       @Override
       public DocIdSet getDocIdSet(final LeafReaderContext context, Bits acceptDocs) {
         LeafReader reader = context.reader();
@@ -223,10 +224,22 @@ abstract class DocSetBase implements DocSet {
 
         }, acceptDocs2);
       }
+
       @Override
       public String toString(String field) {
         return "DocSetTopFilter";
       }
+
+      @Override
+      public boolean equals(Object other) {
+        return sameClassAs(other) &&
+               Objects.equals(bs, getClass().cast(other).bs);
+      }
+
+      @Override
+      public int hashCode() {
+        return classHash() ^ bs.hashCode();
+      }
     };
   }
 

solr/core/src/java/org/apache/solr/search/ExportQParserPlugin.java

@@ -19,15 +19,15 @@ package org.apache.solr.search;
 import org.apache.lucene.util.FixedBitSet;
 import org.apache.solr.handler.component.MergeStrategy;
 import org.apache.solr.request.SolrRequestInfo;
+
 import org.apache.lucene.search.*;
 import org.apache.lucene.index.*;
-import org.apache.solr.common.util.NamedList;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.common.params.SolrParams;
 
 import java.io.IOException;
 import java.util.Map;
-import java.util.Set;
+import java.util.Objects;
 
 public class ExportQParserPlugin extends QParserPlugin {
 
@@ -53,7 +53,6 @@ public class ExportQParserPlugin extends QParserPlugin {
   }
 
   public class ExportQuery extends RankQuery {
-    
     private Query mainQuery;
     private Object id;
 
@@ -94,17 +93,21 @@ public class ExportQParserPlugin extends QParserPlugin {
     }
 
     public int hashCode() {
-      return 31 * super.hashCode() + id.hashCode();
+      return classHash() + 
+          31 * id.hashCode() +
+          31 * Objects.hash(mainQuery);
+    }
+
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             equalsTo(getClass().cast(other));
     }
     
-    public boolean equals(Object o) {
-      if (super.equals(o) == false) {
-        return false;
-      }
-      ExportQuery q = (ExportQuery)o;
-      return id == q.id;
+    private boolean equalsTo(ExportQuery other) {
+      return Objects.equals(id, other.id) &&
+             Objects.equals(mainQuery, other.mainQuery);
     }
-    
+
     public String toString(String s) {
       return s;
     }

solr/core/src/java/org/apache/solr/search/ExtendedQueryBase.java

@@ -18,7 +18,7 @@ package org.apache.solr.search;
 
 import org.apache.lucene.search.Query;
 
-public class ExtendedQueryBase extends Query implements ExtendedQuery {
+public abstract class ExtendedQueryBase extends Query implements ExtendedQuery {
   private int cost;
   private boolean cache = true;
   private boolean cacheSep;

solr/core/src/java/org/apache/solr/search/GraphTermsQParserPlugin.java

@@ -149,16 +149,12 @@ public class GraphTermsQParserPlugin extends QParserPlugin {
     }
 
     public int hashCode() {
-      return 31 * super.hashCode() + id.hashCode();
+      return 31 * classHash() + id.hashCode();
     }
 
-    public boolean equals(Object o) {
-      if (super.equals(o) == false) {
-        return false;
-      }
-
-      GraphTermsQuery q = (GraphTermsQuery)o;
-      return id == q.id;
+    public boolean equals(Object other) {
+      return sameClassAs(other) &&
+             id == ((GraphTermsQuery) other).id;
     }
 
     public GraphTermsQuery clone() {