diff --git a/lucene/src/java/org/apache/lucene/util/BytesRef.java b/lucene/src/java/org/apache/lucene/util/BytesRef.java
index 5cbb610b566..19829bca509 100644
--- a/lucene/src/java/org/apache/lucene/util/BytesRef.java
+++ b/lucene/src/java/org/apache/lucene/util/BytesRef.java
@@ -25,8 +25,6 @@ import java.util.Comparator;
  *
  *  @lucene.experimental */
 public final class BytesRef implements Comparable<BytesRef>,Cloneable {
-
-  static final int HASH_PRIME = 31;
   public static final byte[] EMPTY_BYTES = new byte[0]; 
 
   /** The contents of the BytesRef. Should never be {@code null}. */
@@ -142,12 +140,12 @@ public final class BytesRef implements Comparable<BytesRef>,Cloneable {
    */
   @Override
   public int hashCode() {
-    int result = 0;
+    int hash = 0;
     final int end = offset + length;
     for(int i=offset;i<end;i++) {
-      result = HASH_PRIME * result + bytes[i];
+      hash = 31 * hash + bytes[i];
     }
-    return result;
+    return hash;
   }
 
   @Override
@@ -155,7 +153,10 @@ public final class BytesRef implements Comparable<BytesRef>,Cloneable {
     if (other == null) {
       return false;
     }
-    return this.bytesEquals((BytesRef) other);
+    if (other instanceof BytesRef) {
+      return this.bytesEquals((BytesRef) other);
+    }
+    return false;
   }
 
   /** Interprets stored bytes as UTF8 bytes, returning the
diff --git a/lucene/src/java/org/apache/lucene/util/BytesRefHash.java b/lucene/src/java/org/apache/lucene/util/BytesRefHash.java
index 72b013d0187..6088605df72 100644
--- a/lucene/src/java/org/apache/lucene/util/BytesRefHash.java
+++ b/lucene/src/java/org/apache/lucene/util/BytesRefHash.java
@@ -432,7 +432,7 @@ public final class BytesRefHash {
 
           final int endPos = pos + len;
           while (pos < endPos) {
-            code = BytesRef.HASH_PRIME * code + bytes[pos++];
+            code = 31 * code + bytes[pos++];
           }
         } else {
           code = bytesStart[e0];
diff --git a/lucene/src/java/org/apache/lucene/util/CharsRef.java b/lucene/src/java/org/apache/lucene/util/CharsRef.java
index 6a8c853165f..4d2a9c5389a 100644
--- a/lucene/src/java/org/apache/lucene/util/CharsRef.java
+++ b/lucene/src/java/org/apache/lucene/util/CharsRef.java
@@ -26,7 +26,7 @@ import java.util.Comparator;
  * @lucene.internal
  */
 public final class CharsRef implements Comparable<CharsRef>, CharSequence, Cloneable {
-  private static final char[] EMPTY_ARRAY = new char[0];
+  private static final char[] EMPTY_CHARS = new char[0];
   public char[] chars;
   public int offset;
   public int length;
@@ -35,7 +35,7 @@ public final class CharsRef implements Comparable<CharsRef>, CharSequence, Clone
    * Creates a new {@link CharsRef} initialized an empty array zero-length
    */
   public CharsRef() {
-    this(EMPTY_ARRAY, 0, 0);
+    this(EMPTY_CHARS, 0, 0);
   }
 
   /**
@@ -86,26 +86,11 @@ public final class CharsRef implements Comparable<CharsRef>, CharSequence, Clone
 
   @Override
   public boolean equals(Object other) {
-    if (this == other) {
-      return true;
+    if (other == null) {
+      return false;
     }
-
     if (other instanceof CharsRef) {
-      return charsEquals((CharsRef) other);
-    }
-
-    if (other instanceof CharSequence) {
-      final CharSequence seq = (CharSequence) other;
-      if (length == seq.length()) {
-        int n = length;
-        int i = offset;
-        int j = 0;
-        while (n-- != 0) {
-          if (chars[i++] != seq.charAt(j++))
-            return false;
-        }
-        return true;
-      }
+      return this.charsEquals((CharsRef) other);
     }
     return false;
   }
diff --git a/lucene/src/java/org/apache/lucene/util/IntsRef.java b/lucene/src/java/org/apache/lucene/util/IntsRef.java
index 982df20fcdf..e2a4dc9d5f8 100644
--- a/lucene/src/java/org/apache/lucene/util/IntsRef.java
+++ b/lucene/src/java/org/apache/lucene/util/IntsRef.java
@@ -31,6 +31,7 @@ public final class IntsRef implements Comparable<IntsRef>, Cloneable {
   public int length;
 
   public IntsRef() {
+    ints = EMPTY_INTS;
   }
 
   public IntsRef(int capacity) {
@@ -38,6 +39,7 @@ public final class IntsRef implements Comparable<IntsRef>, Cloneable {
   }
 
   public IntsRef(int[] ints, int offset, int length) {
+    assert ints != null;
     this.ints = ints;
     this.offset = offset;
     this.length = length;
@@ -61,7 +63,13 @@ public final class IntsRef implements Comparable<IntsRef>, Cloneable {
   
   @Override
   public boolean equals(Object other) {
-    return this.intsEquals((IntsRef) other);
+    if (other == null) {
+      return false;
+    }
+    if (other instanceof IntsRef) {
+      return this.intsEquals((IntsRef) other);
+    }
+    return false;
   }
 
   public boolean intsEquals(IntsRef other) {
diff --git a/lucene/src/test/org/apache/lucene/util/TestUnicodeUtil.java b/lucene/src/test/org/apache/lucene/util/TestUnicodeUtil.java
index 55a4f4da5c7..32d39c091f3 100644
--- a/lucene/src/test/org/apache/lucene/util/TestUnicodeUtil.java
+++ b/lucene/src/test/org/apache/lucene/util/TestUnicodeUtil.java
@@ -178,8 +178,6 @@ public class TestUnicodeUtil extends LuceneTestCase {
       CharsRef cRef = new CharsRef(arr, offset, len);
       UnicodeUtil.UTF8toUTF16(ref, cRef);
       assertEquals(cRef.toString(), unicode);
-      assertEquals(cRef, unicode); // CharSeq
-      assertEquals(cRef, ref.utf8ToString()); // CharSeq
     }
   }
 }