Remove redundant field initializers (#13060)

Make protected fields in final classes private.

lucene/analysis/common/src/java/org/apache/lucene/analysis/minhash/MinHashFilter.java

@@ -59,11 +59,11 @@ public class MinHashFilter extends TokenFilter {
 
   private final List<List<FixedSizeTreeSet<LongPair>>> minHashSets;
 
-  private int hashSetSize = DEFAULT_HASH_SET_SIZE;
+  private final int hashSetSize;
 
-  private int bucketCount = DEFAULT_BUCKET_COUNT;
+  private final int bucketCount;
 
-  private int hashCount = DEFAULT_HASH_COUNT;
+  private final int hashCount;
 
   private boolean requiresInitialisation = true;
 

lucene/analysis/common/src/java/org/apache/lucene/analysis/minhash/MinHashFilterFactory.java

@@ -32,13 +32,13 @@ public class MinHashFilterFactory extends TokenFilterFactory {
   /** SPI name */
   public static final String NAME = "minHash";
 
-  private int hashCount = MinHashFilter.DEFAULT_HASH_COUNT;
+  private final int hashCount;
 
-  private int bucketCount = MinHashFilter.DEFAULT_BUCKET_COUNT;
+  private final int bucketCount;
 
-  private int hashSetSize = MinHashFilter.DEFAULT_HASH_SET_SIZE;
+  private final int hashSetSize;
 
-  private boolean withRotation;
+  private final boolean withRotation;
 
   /** Create a {@link MinHashFilterFactory}. */
   public MinHashFilterFactory(Map<String, String> args) {

lucene/analysis/common/src/java/org/apache/lucene/analysis/miscellaneous/WordDelimiterGraphFilterFactory.java

@@ -67,7 +67,7 @@ public class WordDelimiterGraphFilterFactory extends TokenFilterFactory
   private final int flags;
   byte[] typeTable = null;
   private CharArraySet protectedWords = null;
-  private boolean adjustOffsets = false;
+  private final boolean adjustOffsets;
 
   /** Creates a new WordDelimiterGraphFilterFactory */
   public WordDelimiterGraphFilterFactory(Map<String, String> args) {

lucene/analysis/common/src/java/org/apache/lucene/analysis/nl/DutchAnalyzer.java

@@ -89,7 +89,7 @@ public final class DutchAnalyzer extends Analyzer {
   private final CharArraySet stoptable;
 
   /** Contains words that should be indexed but not stemmed. */
-  private CharArraySet excltable = CharArraySet.EMPTY_SET;
+  private final CharArraySet excltable;
 
   private final StemmerOverrideMap stemdict;
 

lucene/analysis/common/src/java/org/apache/lucene/analysis/pattern/PatternCaptureGroupFilterFactory.java

@@ -41,8 +41,8 @@ public class PatternCaptureGroupFilterFactory extends TokenFilterFactory {
   /** SPI name */
   public static final String NAME = "patternCaptureGroup";
 
-  private Pattern pattern;
-  private boolean preserveOriginal = true;
+  private final Pattern pattern;
+  private final boolean preserveOriginal;
 
   public PatternCaptureGroupFilterFactory(Map<String, String> args) {
     super(args);

lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/JapaneseTokenizerFactory.java

@@ -114,7 +114,7 @@ public class JapaneseTokenizerFactory extends TokenizerFactory implements Resour
    * /箱根山-箱根/成田空港-成田/ requests "箱根" and "成田" to be in the result in NBEST output.
    */
   private final String nbestExamples;
-  private int nbestCost = -1;
+  private int nbestCost;
 
   /** Creates a new JapaneseTokenizerFactory */
   public JapaneseTokenizerFactory(Map<String, String> args) {

lucene/analysis/opennlp/src/java/org/apache/lucene/analysis/opennlp/OpenNLPTokenizer.java

@@ -44,7 +44,7 @@ public final class OpenNLPTokenizer extends SegmentingTokenizerBase {
   private int sentenceStart = 0;
   private int sentenceIndex = -1;
 
-  private NLPTokenizerOp tokenizerOp = null;
+  private final NLPTokenizerOp tokenizerOp;
 
   public OpenNLPTokenizer(
       AttributeFactory factory, NLPSentenceDetectorOp sentenceOp, NLPTokenizerOp tokenizerOp)

lucene/analysis/opennlp/src/java/org/apache/lucene/analysis/opennlp/tools/NLPChunkerOp.java

@@ -23,7 +23,7 @@ import opennlp.tools.chunker.ChunkerModel;
 
 /** Supply OpenNLP Chunking tool Requires binary models from OpenNLP project on SourceForge. */
 public class NLPChunkerOp {
-  private ChunkerME chunker = null;
+  private final ChunkerME chunker;
 
   public NLPChunkerOp(ChunkerModel chunkerModel) throws IOException {
     chunker = new ChunkerME(chunkerModel);

lucene/analysis/opennlp/src/java/org/apache/lucene/analysis/opennlp/tools/NLPPOSTaggerOp.java

@@ -27,7 +27,7 @@ import opennlp.tools.postag.POSTaggerME;
  * SourceForge.
  */
 public class NLPPOSTaggerOp {
-  private POSTagger tagger = null;
+  private final POSTagger tagger;
 
   public NLPPOSTaggerOp(POSModel model) throws IOException {
     tagger = new POSTaggerME(model);

lucene/analysis/phonetic/src/java/org/apache/lucene/analysis/phonetic/DaitchMokotoffSoundexFilter.java

@@ -32,10 +32,10 @@ import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  */
 public final class DaitchMokotoffSoundexFilter extends TokenFilter {
   /** true if encoded tokens should be added as synonyms */
-  protected boolean inject = true;
+  private final boolean inject;
 
   /** phonetic encoder */
-  protected DaitchMokotoffSoundex encoder = new DaitchMokotoffSoundex();
+  private final DaitchMokotoffSoundex encoder = new DaitchMokotoffSoundex();
 
   // output is a string such as ab|ac|...
   private static final Pattern pattern = Pattern.compile("([^|]+)");

lucene/analysis/phonetic/src/java/org/apache/lucene/analysis/phonetic/PhoneticFilter.java

@@ -32,13 +32,13 @@ import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  */
 public final class PhoneticFilter extends TokenFilter {
   /** true if encoded tokens should be added as synonyms */
-  protected boolean inject = true;
+  private final boolean inject;
 
   /** phonetic encoder */
-  protected Encoder encoder = null;
+  private final Encoder encoder;
 
   /** captured state, non-null when <code>inject=true</code> and a token is buffered */
-  protected State save = null;
+  private State save = null;
 
   private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
   private final PositionIncrementAttribute posAtt = addAttribute(PositionIncrementAttribute.class);

lucene/analysis/stempel/src/java/org/egothor/stemmer/Trie.java

@@ -73,7 +73,7 @@ public class Trie {
   List<CharSequence> cmds = new ArrayList<>();
   int root;
 
-  boolean forward = false;
+  boolean forward;
 
   /**
    * Constructor for the Trie object.

lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/TaskSequence.java

@@ -43,7 +43,7 @@ public class TaskSequence extends PerfTask {
   private boolean resetExhausted = false;
   private PerfTask[] tasksArray;
   private boolean anyExhaustibleTasks;
-  private boolean collapsable = false; // to not collapse external sequence named in alg.
+  private final boolean collapsable; // to not collapse external sequence named in alg.
 
   private boolean fixedTime; // true if we run for fixed time
   private double runTimeSec; // how long to run for

lucene/benchmark/src/test/org/apache/lucene/benchmark/byTask/feeds/TestTrecContentSource.java

@@ -36,7 +36,7 @@ public class TestTrecContentSource extends LuceneTestCase {
   /** A TrecDocMaker which works on a String and not files. */
   private static class StringableTrecSource extends TrecContentSource {
 
-    private String docs = null;
+    private final String docs;
 
     public StringableTrecSource(String docs, boolean forever) {
       this.docs = docs;

lucene/core/src/java/org/apache/lucene/index/FieldInfo.java

@@ -32,7 +32,7 @@ public final class FieldInfo {
   /** Internal field number */
   public final int number;
 
-  private DocValuesType docValuesType = DocValuesType.NONE;
+  private DocValuesType docValuesType;
 
   // True if any document indexed term vectors
   private boolean storeTermVector;

lucene/core/src/java/org/apache/lucene/index/LiveIndexWriterConfig.java

@@ -84,7 +84,7 @@ public class LiveIndexWriterConfig {
   protected volatile int perThreadHardLimitMB;
 
   /** True if segment flushes should use compound file format */
-  protected volatile boolean useCompoundFile = IndexWriterConfig.DEFAULT_USE_COMPOUND_FILE_SYSTEM;
+  protected volatile boolean useCompoundFile;
 
   /** True if calls to {@link IndexWriter#close()} should first do a commit. */
   protected boolean commitOnClose = IndexWriterConfig.DEFAULT_COMMIT_ON_CLOSE;

lucene/core/src/java/org/apache/lucene/index/MergePolicy.java

@@ -597,12 +597,12 @@ public abstract class MergePolicy {
    * If the size of the merge segment exceeds this ratio of the total index size then it will remain
    * in non-compound format
    */
-  protected double noCFSRatio = DEFAULT_NO_CFS_RATIO;
+  protected double noCFSRatio;
 
   /**
    * If the size of the merged segment exceeds this value then it will not use compound file format.
    */
-  protected long maxCFSSegmentSize = DEFAULT_MAX_CFS_SEGMENT_SIZE;
+  protected long maxCFSSegmentSize;
 
   /** Creates a new merge policy instance. */
   protected MergePolicy() {

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

@@ -120,7 +120,7 @@ final class WANDScorer extends Scorer {
 
   private final int scalingFactor;
   // scaled min competitive score
-  private long minCompetitiveScore = 0;
+  private long minCompetitiveScore;
 
   private final Scorer[] allScorers;
 

lucene/core/src/java/org/apache/lucene/search/comparators/TermOrdValComparator.java

@@ -89,7 +89,7 @@ public class TermOrdValComparator extends FieldComparator<BytesRef> {
   private boolean singleSort;
 
   /** Whether this comparator is allowed to skip documents. */
-  private boolean canSkipDocuments = true;
+  private boolean canSkipDocuments;
 
   /** Whether the collector is done with counting hits so that we can start skipping documents. */
   private boolean hitsThresholdReached = false;

lucene/core/src/java/org/apache/lucene/util/RoaringDocIdSet.java

@@ -253,7 +253,7 @@ public class RoaringDocIdSet extends DocIdSet {
   private class Iterator extends DocIdSetIterator {
 
     int block;
-    DocIdSetIterator sub = null;
+    DocIdSetIterator sub;
     int doc;
 
     Iterator() throws IOException {

lucene/core/src/java/org/apache/lucene/util/automaton/LimitedFiniteStringsIterator.java

@@ -31,7 +31,7 @@ import org.apache.lucene.util.IntsRef;
  */
 public class LimitedFiniteStringsIterator extends FiniteStringsIterator {
   /** Maximum number of finite strings to create. */
-  private int limit = Integer.MAX_VALUE;
+  private final int limit;
 
   /** Number of generated finite strings. */
   private int count = 0;

lucene/highlighter/src/java/org/apache/lucene/search/uhighlight/OffsetsEnum.java

@@ -123,7 +123,7 @@ public abstract class OffsetsEnum implements Comparable<OffsetsEnum>, Closeable
     private final PostingsEnum postingsEnum; // with offsets
     private final int freq;
 
-    private int posCounter = -1;
+    private int posCounter;
 
     public OfPostings(BytesRef term, int freq, PostingsEnum postingsEnum) throws IOException {
       this.term = Objects.requireNonNull(term);

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/BoostQueryNode.java

@@ -30,7 +30,7 @@ import org.apache.lucene.queryparser.flexible.messages.MessageImpl;
  */
 public class BoostQueryNode extends QueryNodeImpl {
 
-  private float value = 0;
+  private float value;
 
   /**
    * Constructs a boost node

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/ModifierQueryNode.java

@@ -84,7 +84,7 @@ public class ModifierQueryNode extends QueryNodeImpl {
     }
   }
 
-  private Modifier modifier = Modifier.MOD_NONE;
+  private Modifier modifier;
 
   /**
    * Used to store the modifier value on the original query string

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/OpaqueQueryNode.java

@@ -25,9 +25,9 @@ import org.apache.lucene.queryparser.flexible.core.parser.EscapeQuerySyntax;
  */
 public class OpaqueQueryNode extends QueryNodeImpl {
 
-  private CharSequence schema = null;
+  private CharSequence schema;
 
-  private CharSequence value = null;
+  private CharSequence value;
 
   /**
    * @param schema - schema identifier

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/PathQueryNode.java

@@ -41,7 +41,7 @@ public class PathQueryNode extends QueryNodeImpl {
 
   /** Term text with a beginning and end position */
   public static class QueryText implements Cloneable {
-    CharSequence value = null;
+    CharSequence value;
 
     /** != null The term's begin position. */
     int begin;
@@ -97,7 +97,7 @@ public class PathQueryNode extends QueryNodeImpl {
     }
   }
 
-  private List<QueryText> values = null;
+  private List<QueryText> values;
 
   /**
    * @param pathElements - List of QueryText objects

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/PhraseSlopQueryNode.java

@@ -25,7 +25,7 @@ import org.apache.lucene.search.PhraseQuery; // javadocs
 /** Query node for {@link PhraseQuery}'s slop factor. */
 public class PhraseSlopQueryNode extends QueryNodeImpl implements FieldableNode {
 
-  private int value = 0;
+  private int value;
 
   /**
    * @exception QueryNodeError throw in overridden method to disallow

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/ProximityQueryNode.java

@@ -57,9 +57,9 @@ public class ProximityQueryNode extends BooleanQueryNode {
 
   /** utility class containing the distance condition and number */
   public static class ProximityType {
-    int pDistance = 0;
+    int pDistance;
 
-    Type pType = null;
+    Type pType;
 
     public ProximityType(Type type) {
       this(type, 0);
@@ -71,10 +71,10 @@ public class ProximityQueryNode extends BooleanQueryNode {
     }
   }
 
-  private Type proximityType = Type.SENTENCE;
+  private Type proximityType;
   private int distance = -1;
-  private boolean inorder = false;
-  private CharSequence field = null;
+  private final boolean inorder;
+  private CharSequence field;
 
   /**
    * @param clauses - QueryNode children

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/core/nodes/SlopQueryNode.java

@@ -32,7 +32,7 @@ import org.apache.lucene.queryparser.flexible.messages.MessageImpl;
  */
 public class SlopQueryNode extends QueryNodeImpl implements FieldableNode {
 
-  private int value = 0;
+  private int value;
 
   /**
    * @param query - QueryNode Tree with the phrase

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/standard/config/FieldBoostMapFCListener.java

@@ -34,7 +34,7 @@ import org.apache.lucene.queryparser.flexible.standard.config.StandardQueryConfi
  */
 public class FieldBoostMapFCListener implements FieldConfigListener {
 
-  private QueryConfigHandler config = null;
+  private final QueryConfigHandler config;
 
   public FieldBoostMapFCListener(QueryConfigHandler config) {
     this.config = config;

lucene/queryparser/src/java/org/apache/lucene/queryparser/flexible/standard/config/FieldDateResolutionFCListener.java

@@ -36,7 +36,7 @@ import org.apache.lucene.queryparser.flexible.standard.config.StandardQueryConfi
  */
 public class FieldDateResolutionFCListener implements FieldConfigListener {
 
-  private QueryConfigHandler config = null;
+  private final QueryConfigHandler config;
 
   public FieldDateResolutionFCListener(QueryConfigHandler config) {
     this.config = config;

lucene/test-framework/src/java/org/apache/lucene/tests/index/DocHelper.java

@@ -175,7 +175,7 @@ public class DocHelper {
   public static Field textUtfField2 =
       new Field(TEXT_FIELD_UTF2_KEY, FIELD_UTF2_TEXT, TEXT_TYPE_STORED_WITH_TVS);
 
-  public static Map<String, Object> nameValues = null;
+  public static Map<String, Object> nameValues;
 
   // ordered list of all the fields...
   // could use LinkedHashMap for this purpose if Java1.4 is OK