Add missing @Override annotations

runtime/Java/src/org/antlr/v4/runtime/ANTLRInputStream.java

@@ -225,5 +225,6 @@ public class ANTLRInputStream implements CharStream {
 		return name;
 	}
 
+    @Override
     public String toString() { return new String(data); }
 }

runtime/Java/src/org/antlr/v4/runtime/BufferedTokenStream.java

@@ -234,6 +234,7 @@ public class BufferedTokenStream<T extends Token> implements TokenStream {
     public String getSourceName() {	return tokenSource.getSourceName();	}
 
     /** Grab *all* tokens from stream and return string */
+    @Override
     public String toString() {
         if ( p == -1 ) setup();
         fill();

runtime/Java/src/org/antlr/v4/runtime/CommonToken.java

@@ -195,6 +195,7 @@ public class CommonToken implements WritableToken, Serializable {
 		return source != null ? source.getInputStream() : null;
 	}
 
+	@Override
 	public String toString() {
 		String channelStr = "";
 		if ( channel>0 ) {

runtime/Java/src/org/antlr/v4/runtime/TokenRewriteStream.java

@@ -353,6 +353,7 @@ public class TokenRewriteStream extends CommonTokenStream {
 		return buf.toString();
 	}
 
+	@Override
 	public String toString() {
         fill();
 		return toString(MIN_TOKEN_INDEX, size()-1);

runtime/Java/src/org/antlr/v4/runtime/atn/ActionTransition.java

@@ -52,6 +52,7 @@ public class ActionTransition extends Transition {
 		return true; // we are to be ignored by analysis 'cept for predicates
 	}
 
+	@Override
 	public String toString() {
 		return "action_"+ruleIndex+":"+actionIndex;
 	}

runtime/Java/src/org/antlr/v4/runtime/atn/LexerATNSimulator.java

@@ -179,6 +179,7 @@ public class LexerATNSimulator extends ATNSimulator {
 		}
 	}
 
+	@Override
 	public void reset() {
 		dfaPrevAccept.reset();
 		atnPrevAccept.reset();

runtime/Java/src/org/antlr/v4/runtime/misc/FastQueue.java

@@ -87,6 +87,7 @@ public class FastQueue<T> {
     }
 
     /** Return string of current buffer contents; non-destructive */
+    @Override
     public String toString() {
         StringBuilder buf = new StringBuilder();
         int n = size();

runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java

@@ -62,6 +62,7 @@ public interface IntSet {
 
     boolean isNil();
 
+    @Override
     boolean equals(Object obj);
 
     int getSingleElement();
@@ -73,5 +74,6 @@ public interface IntSet {
 
     List<Integer> toList();
 
+    @Override
     String toString();
 }

runtime/Java/src/org/antlr/v4/runtime/misc/Interval.java

@@ -64,6 +64,7 @@ public class Interval {
 		return cache[a];
 	}
 
+	@Override
 	public boolean equals(Object o) {
 		if ( o==null ) {
 			return false;
@@ -139,6 +140,7 @@ public class Interval {
 		return diff;
 	}
 
+	@Override
 	public String toString() {
 		return a+".."+b;
 	}

runtime/Java/src/org/antlr/v4/runtime/misc/OrderedHashSet.java

@@ -124,6 +124,7 @@ public class OrderedHashSet<T> extends LinkedHashSet<T> {
 		return elements.toArray();
 	}
 
+	@Override
 	public String toString() {
         return elements.toString();
     }

tool/src/org/antlr/v4/automata/LexerATNFactory.java

@@ -58,6 +58,7 @@ public class LexerATNFactory extends ParserATNFactory {
 		codegenTemplates = gen.templates;
 	}
 
+	@Override
 	public ATN createATN() {
 		// BUILD ALL START STATES (ONE PER MODE)
 		Set<String> modes = ((LexerGrammar) g).modes.keySet();

tool/src/org/antlr/v4/automata/ParserATNFactory.java

@@ -105,6 +105,7 @@ public class ParserATNFactory implements ATNFactory {
 
 	public ParserATNFactory(@NotNull Grammar g) { this.g = g; atn = new ATN(); }
 
+	@Override
 	public ATN createATN() {
 		_createATN(g.rules.values());
 		atn.maxTokenType = g.getMaxTokenType();
@@ -133,6 +134,7 @@ public class ParserATNFactory implements ATNFactory {
 		}
 	}
 
+	@Override
 	public void setCurrentRuleName(String name) {
 		this.currentRule = g.getRule(name);
 	}
@@ -143,6 +145,7 @@ public class ParserATNFactory implements ATNFactory {
 	}
 
 	/* start->ruleblock->end */
+	@Override
 	public Handle rule(GrammarAST ruleAST, String name, Handle blk) {
 		Rule r = g.getRule(name);
 		RuleStartState start = atn.ruleToStartState[r.index];
@@ -157,6 +160,7 @@ public class ParserATNFactory implements ATNFactory {
 	}
 
 	/** From label A build Graph o-A->o */
+	@Override
 	public Handle tokenRef(TerminalAST node) {
 		ATNState left = newState(node);
 		ATNState right = newState(node);
@@ -170,6 +174,7 @@ public class ParserATNFactory implements ATNFactory {
      *  what an alt block looks like, must have extra state on left.
 	 *  This handles ~A also, converted to ~{A} set.
      */
+	@Override
 	public Handle set(GrammarAST associatedAST, List<GrammarAST> terminals, boolean invert) {
 		ATNState left = newState(associatedAST);
 		ATNState right = newState(associatedAST);
@@ -188,11 +193,13 @@ public class ParserATNFactory implements ATNFactory {
 		return new Handle(left, right);
 	}
 
+	@Override
 	public Handle tree(GrammarAST node, List<Handle> els) {
 		throw new UnsupportedOperationException("^(...) not allowed in non-tree grammar");
 	}
 
 	/** Not valid for non-lexers */
+	@Override
 	public Handle range(GrammarAST a, GrammarAST b) {
 		throw new UnsupportedOperationException();
 	}
@@ -209,6 +216,7 @@ public class ParserATNFactory implements ATNFactory {
 	}
 
 	/** For a non-lexer, just build a simple token reference atom. */
+	@Override
 	public Handle stringLiteral(TerminalAST stringLiteralAST) {
 		return tokenRef(stringLiteralAST);
 	}
@@ -226,6 +234,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *  where (r) is the start of rule r and the trailing o is not linked
 	 *  to from rule ref state directly (uses followState).
 	 */
+	@Override
 	public Handle ruleRef(GrammarAST node) {
 		Handle h = _ruleRef(node);
 //		Rule r = g.getRule(node.getText());
@@ -257,6 +266,7 @@ public class ParserATNFactory implements ATNFactory {
 	}
 
 	/** From an empty alternative build  o-e->o */
+	@Override
 	public Handle epsilon(GrammarAST node) {
 		ATNState left = newState(node);
 		ATNState right = newState(node);
@@ -269,6 +279,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *  predicate action.  The pred is a pointer into the AST of
 	 *  the SEMPRED token.
 	 */
+	@Override
 	public Handle sempred(PredAST pred) {
 		//System.out.println("sempred: "+ pred);
 		ATNState left = newState(pred);
@@ -284,6 +295,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *  The action goes into ATN though it is ignored during prediction
 	 *  if actionIndex < 0.  Only forced are executed during prediction.
 	 */
+	@Override
 	public Handle action(ActionAST action) {
 		//System.out.println("action: "+action);
 		ATNState left = newState(action);
@@ -320,6 +332,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *
 	 *  TODO: Set alt number (1..n) in the states?
 	 */
+	@Override
 	public Handle block(BlockAST blkAST, GrammarAST ebnfRoot, List<Handle> alts) {
 		if ( ebnfRoot==null ) {
 			if ( alts.size()==1 ) {
@@ -371,6 +384,7 @@ public class ParserATNFactory implements ATNFactory {
 	}
 
 	@NotNull
+	@Override
 	public Handle alt(@NotNull List<Handle> els) {
 		return elemList(els);
 	}
@@ -415,6 +429,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *  or, if A is a block, just add an empty alt to the end of the block
 	 */
 	@NotNull
+	@Override
 	public Handle optional(@NotNull GrammarAST optAST, @NotNull Handle blk) {
 		// TODO: no such thing as nongreedy ()? so give error
 		BlockStartState blkStart = (BlockStartState)blk.left;
@@ -433,6 +448,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *  blk start.
 	 */
 	@NotNull
+	@Override
 	public Handle plus(@NotNull GrammarAST plusAST, @NotNull Handle blk) {
 		PlusBlockStartState blkStart = (PlusBlockStartState)blk.left;
 		BlockEndState blkEnd = (BlockEndState)blk.right;
@@ -474,6 +490,7 @@ public class ParserATNFactory implements ATNFactory {
 	 *  not the same thing as (A|B|)+.
 	 */
 	@NotNull
+	@Override
 	public Handle star(@NotNull GrammarAST starAST, @NotNull Handle elem) {
 		StarBlockStartState blkStart = (StarBlockStartState)elem.left;
 		BlockEndState blkEnd = (BlockEndState)elem.right;
@@ -505,6 +522,7 @@ public class ParserATNFactory implements ATNFactory {
 
 	/** Build an atom with all possible values in its label */
 	@NotNull
+	@Override
 	public Handle wildcard(GrammarAST node) {
 		ATNState left = newState(node);
 		ATNState right = newState(node);
@@ -516,6 +534,7 @@ public class ParserATNFactory implements ATNFactory {
 	/** Build a subrule matching ^(. .*) (any tree or node). Let's use
 	 *  (^(. .+) | .) to be safe.
 	 */
+	@Override
 	public Handle wildcardTree(GrammarAST associatedAST) { throw new UnsupportedOperationException(); }
 
 	void epsilon(ATNState a, @NotNull ATNState b) {
@@ -572,10 +591,12 @@ public class ParserATNFactory implements ATNFactory {
 		return n;
 	}
 
+	@Override
 	public Handle label(Handle t) {
 		return t;
 	}
 
+	@Override
 	public Handle listLabel(Handle t) {
 		return t;
 	}
@@ -606,6 +627,7 @@ public class ParserATNFactory implements ATNFactory {
 	}
 
 	@NotNull
+	@Override
 	public ATNState newState() { return newState(null); }
 
 	public boolean isGreedy(@NotNull BlockAST blkAST) {

tool/src/org/antlr/v4/codegen/ActionTranslator.java

@@ -130,6 +130,7 @@ public class ActionTranslator implements ActionSplitterListener {
 		return translator.chunks;
 	}
 
+	@Override
 	public void attr(String expr, Token x) {
 		gen.g.tool.log("action-translator", "attr "+x);
 		Attribute a = node.resolver.resolveToAttribute(x.getText(), node);
@@ -160,6 +161,7 @@ public class ActionTranslator implements ActionSplitterListener {
 	}
 
 	/** $x.y = expr; */
+	@Override
 	public void setQualifiedAttr(String expr, Token x, Token y, Token rhs) {
 		gen.g.tool.log("action-translator", "setQAttr "+x+"."+y+"="+rhs);
 		// x has to be current rule; just set y attr
@@ -167,6 +169,7 @@ public class ActionTranslator implements ActionSplitterListener {
 		chunks.add(new SetAttr(nodeContext,y.getText(), rhsChunks));
 	}
 
+	@Override
 	public void qualifiedAttr(String expr, Token x, Token y) {
 		gen.g.tool.log("action-translator", "qattr "+x+"."+y);
 		Attribute a = node.resolver.resolveToAttribute(x.getText(), y.getText(), node);
@@ -197,6 +200,7 @@ public class ActionTranslator implements ActionSplitterListener {
 		}
 	}
 
+	@Override
 	public void setAttr(String expr, Token x, Token rhs) {
 		gen.g.tool.log("action-translator", "setAttr "+x+" "+rhs);
 		List<ActionChunk> rhsChunks = translateActionChunk(factory,rf,rhs.getText(),node);
@@ -205,12 +209,14 @@ public class ActionTranslator implements ActionSplitterListener {
 		chunks.add(s);
 	}
 
+	@Override
 	public void nonLocalAttr(String expr, Token x, Token y) {
 		gen.g.tool.log("action-translator", "nonLocalAttr "+x+"::"+y);
 		Rule r = factory.getGrammar().getRule(x.getText());
 		chunks.add(new NonLocalAttrRef(nodeContext, x.getText(), y.getText(), r.index));
 	}
 
+	@Override
 	public void setNonLocalAttr(String expr, Token x, Token y, Token rhs) {
 		gen.g.tool.log("action-translator", "setNonLocalAttr "+x+"::"+y+"="+rhs);
 		Rule r = factory.getGrammar().getRule(x.getText());
@@ -219,9 +225,11 @@ public class ActionTranslator implements ActionSplitterListener {
 		chunks.add(s);
 	}
 
+	@Override
 	public void unknownSyntax(Token t) {
 	}
 
+	@Override
 	public void text(String text) {
 		chunks.add(new ActionText(nodeContext,text));
 	}

tool/src/org/antlr/v4/codegen/BlankOutputModelFactory.java

@@ -37,60 +37,85 @@ import org.antlr.v4.tool.ast.*;
 import java.util.List;
 
 public abstract class BlankOutputModelFactory implements OutputModelFactory {
+	@Override
 	public ParserFile parserFile(String fileName) { return null; }
 
+	@Override
 	public Parser parser(ParserFile file) { return null; }
 
+	@Override
 	public RuleFunction rule(Rule r) { return null; }
 
+	@Override
 	public List<SrcOp> rulePostamble(RuleFunction function, Rule r) { return null; }
 
+	@Override
 	public LexerFile lexerFile(String fileName) { return null; }
 
+	@Override
 	public Lexer lexer(LexerFile file) { return null; }
 
 	// ALTERNATIVES / ELEMENTS
 
+	@Override
 	public CodeBlockForAlt alternative(Alternative alt, boolean outerMost) { return null; }
 
+	@Override
 	public CodeBlockForAlt finishAlternative(CodeBlockForAlt blk, List<SrcOp> ops) { return blk; }
 
+	@Override
 	public CodeBlockForAlt epsilon(Alternative alt, boolean outerMost) { return null; }
 
+	@Override
 	public List<SrcOp> ruleRef(GrammarAST ID, GrammarAST label, GrammarAST args) { return null; }
 
+	@Override
 	public List<SrcOp> tokenRef(GrammarAST ID, GrammarAST label, GrammarAST args) { return null; }
 
+	@Override
 	public List<SrcOp> stringRef(GrammarAST ID, GrammarAST label) { return tokenRef(ID, label, null); }
 
+	@Override
 	public List<SrcOp> set(GrammarAST setAST, GrammarAST label, boolean invert) {	return null; }
 
+	@Override
 	public List<SrcOp> wildcard(GrammarAST ast, GrammarAST labelAST) { return null; }
 
 	// ACTIONS
 
+	@Override
 	public List<SrcOp> action(GrammarAST ast) { return null; }
 
+	@Override
 	public List<SrcOp> forcedAction(GrammarAST ast) { return null; }
 
+	@Override
 	public List<SrcOp> sempred(GrammarAST ast) { return null; }
 
 	// BLOCKS
 
+	@Override
 	public Choice getChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts, GrammarAST label) { return null; }
 
+	@Override
 	public Choice getEBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) { return null; }
 
+	@Override
 	public Choice getLL1ChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts) { return null; }
 
+	@Override
 	public Choice getComplexChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts) { return null; }
 
+	@Override
 	public Choice getLL1EBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) { return null; }
 
+	@Override
 	public Choice getComplexEBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) { return null; }
 
+	@Override
 	public List<SrcOp> getLL1Test(IntervalSet look, GrammarAST blkAST) { return null; }
 
+	@Override
 	public boolean needsImplicitLabel(GrammarAST ID, LabeledOp op) { return false; }
 }
 

tool/src/org/antlr/v4/codegen/DefaultOutputModelFactory.java

@@ -68,6 +68,7 @@ public abstract class DefaultOutputModelFactory extends BlankOutputModelFactory
 	// Convenience methods
 
 	@NotNull
+	@Override
 	public Grammar getGrammar() { return g; }
 
 	@Override

tool/src/org/antlr/v4/codegen/ParserFactory.java

@@ -44,14 +44,17 @@ import java.util.List;
 public class ParserFactory extends DefaultOutputModelFactory {
 	public ParserFactory(CodeGenerator gen) { super(gen); }
 
+	@Override
 	public ParserFile parserFile(String fileName) {
 		return new ParserFile(this, fileName);
 	}
 
+	@Override
 	public Parser parser(ParserFile file) {
 		return new Parser(this, file);
 	}
 
+	@Override
 	public RuleFunction rule(Rule r) {
 		if ( r instanceof LeftRecursiveRule ) {
 			return new LeftRecursiveRuleFunction(this, (LeftRecursiveRule)r);
@@ -62,10 +65,12 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		}
 	}
 
+	@Override
 	public CodeBlockForAlt epsilon(Alternative alt, boolean outerMost) {
 		return alternative(alt, outerMost);
 	}
 
+	@Override
 	public CodeBlockForAlt alternative(Alternative alt, boolean outerMost) {
 		if ( outerMost ) return new CodeBlockForOuterMostAlt(this, alt);
 		return new CodeBlockForAlt(this);
@@ -77,10 +82,13 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return blk;
 	}
 
+	@Override
 	public List<SrcOp> action(GrammarAST ast) { return list(new Action(this, ast)); }
 
+	@Override
 	public List<SrcOp> sempred(GrammarAST ast) { return list(new SemPred(this, ast)); }
 
+	@Override
 	public List<SrcOp> ruleRef(GrammarAST ID, GrammarAST label, GrammarAST args) {
 		InvokeRule invokeOp = new InvokeRule(this, ID, label);
 		// If no manual label and action refs as token/rule not label, we need to define implicit label
@@ -89,6 +97,7 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return list(invokeOp, listLabelOp);
 	}
 
+	@Override
 	public List<SrcOp> tokenRef(GrammarAST ID, GrammarAST labelAST, GrammarAST args) {
 		LabeledOp matchOp = new MatchToken(this, (TerminalAST) ID);
 		if ( labelAST!=null ) {
@@ -166,6 +175,7 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return list(wild, listLabelOp);
 	}
 
+	@Override
 	public Choice getChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts, GrammarAST labelAST) {
 		int decision = ((DecisionState)blkAST.atnState).decision;
 		Choice c;
@@ -191,6 +201,7 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return c;
 	}
 
+	@Override
 	public Choice getEBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) {
 		if (!g.tool.force_atn) {
 			int decision;
@@ -212,14 +223,17 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return getComplexEBNFBlock(ebnfRoot, alts);
 	}
 
+	@Override
 	public Choice getLL1ChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts) {
 		return new LL1AltBlock(this, blkAST, alts);
 	}
 
+	@Override
 	public Choice getComplexChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts) {
 		return new AltBlock(this, blkAST, alts);
 	}
 
+	@Override
 	public Choice getLL1EBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) {
 		int ebnf = 0;
 		if ( ebnfRoot!=null ) ebnf = ebnfRoot.getType();
@@ -241,6 +255,7 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return c;
 	}
 
+	@Override
 	public Choice getComplexEBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) {
 		int ebnf = 0;
 		if ( ebnfRoot!=null ) ebnf = ebnfRoot.getType();
@@ -259,10 +274,12 @@ public class ParserFactory extends DefaultOutputModelFactory {
 		return c;
 	}
 
+	@Override
 	public List<SrcOp> getLL1Test(IntervalSet look, GrammarAST blkAST) {
 		return list(new TestSetInline(this, blkAST, look));
 	}
 
+	@Override
 	public boolean needsImplicitLabel(GrammarAST ID, LabeledOp op) {
 		Alternative currentOuterMostAlt = getCurrentOuterMostAlt();
 		boolean actionRefsAsToken = currentOuterMostAlt.tokenRefsInActions.containsKey(ID.getText());

tool/src/org/antlr/v4/codegen/model/InvokeRule.java

@@ -91,6 +91,7 @@ public class InvokeRule extends RuleElement implements LabeledOp {
 		}
 	}
 
+	@Override
 	public List<Decl> getLabels() {
 		return labels.elements();
 	}

tool/src/org/antlr/v4/codegen/model/MatchToken.java

@@ -57,5 +57,6 @@ public class MatchToken extends RuleElement implements LabeledOp {
 		super(factory, ast);
 	}
 
+	@Override
 	public List<Decl> getLabels() { return labels; }
 }

tool/src/org/antlr/v4/misc/Graph.java

@@ -48,6 +48,7 @@ public class Graph {
             if ( !edges.contains(n) ) edges.add(n);
         }
 
+        @Override
         public String toString() { return payload.toString(); }
     }
 

tool/src/org/antlr/v4/parse/GrammarASTAdaptor.java

@@ -42,6 +42,7 @@ public class GrammarASTAdaptor extends CommonTreeAdaptor {
     public GrammarASTAdaptor() { ; }
     public GrammarASTAdaptor(org.antlr.runtime.CharStream input) { this.input = input; }
 
+    @Override
     public Object create(Token token) {
         return new GrammarAST(token);
     }
@@ -66,11 +67,13 @@ public class GrammarASTAdaptor extends CommonTreeAdaptor {
         return t;
     }
 
+    @Override
     public Object dupNode(Object t) {
         if ( t==null ) return null;
         return ((GrammarAST)t).dupNode(); //create(((GrammarAST)t).token);
     }
 
+    @Override
     public Object errorNode(org.antlr.runtime.TokenStream input, org.antlr.runtime.Token start, org.antlr.runtime.Token stop,
                             org.antlr.runtime.RecognitionException e)
     {

tool/src/org/antlr/v4/parse/ToolANTLRParser.java

@@ -44,6 +44,7 @@ public class ToolANTLRParser extends ANTLRParser {
 		this.tool = tool;
 	}
 
+	@Override
 	public void displayRecognitionError(String[] tokenNames,
 										RecognitionException e)
 	{

tool/src/org/antlr/v4/semantics/AttributeChecks.java

@@ -101,12 +101,14 @@ public class AttributeChecks implements ActionSplitterListener {
 
     // LISTENER METHODS
 
+    @Override
     public void setQualifiedAttr(String expr, Token x, Token y, Token rhs) {
 		qualifiedAttr(expr, x, y);
         new AttributeChecks(g, r, alt, node, rhs).examineAction();
     }
 
 	// $x.y
+	@Override
 	public void qualifiedAttr(String expr, Token x, Token y) {
 		if ( node.resolver.resolveToAttribute(x.getText(), y.getText(), node)==null ) {
 			Rule rref = isolatedRuleRef(x.getText());
@@ -131,6 +133,7 @@ public class AttributeChecks implements ActionSplitterListener {
 		}
 	}
 
+	@Override
 	public void setAttr(String expr, Token x, Token rhs) {
 		if ( node.resolver.resolveToAttribute(x.getText(), node)==null ) {
             errMgr.grammarError(ErrorType.UNKNOWN_SIMPLE_ATTRIBUTE,
@@ -139,6 +142,7 @@ public class AttributeChecks implements ActionSplitterListener {
         new AttributeChecks(g, r, alt, node, rhs).examineAction();
     }
 
+	@Override
     public void attr(String expr, Token x) {
 		if ( node.resolver.resolveToAttribute(x.getText(), node)==null ) {
 			if ( node.resolver.resolvesToToken(x.getText(), node) ) {
@@ -157,6 +161,7 @@ public class AttributeChecks implements ActionSplitterListener {
 		}
 	}
 
+	@Override
 	public void nonLocalAttr(String expr, Token x, Token y) {
 		Rule r = g.getRule(x.getText());
 		if ( r==null ) {
@@ -170,6 +175,7 @@ public class AttributeChecks implements ActionSplitterListener {
 		}
 	}
 
+	@Override
 	public void setNonLocalAttr(String expr, Token x, Token y, Token rhs) {
 		Rule r = g.getRule(x.getText());
 		if ( r==null ) {
@@ -183,11 +189,13 @@ public class AttributeChecks implements ActionSplitterListener {
 		}
 	}
 
+	@Override
 	public void unknownSyntax(Token t) {
 		errMgr.grammarError(ErrorType.INVALID_TEMPLATE_ACTION,
 							g.fileName, t, t.getText());
 	}
 
+	@Override
 	public void text(String text) { }
 
 	// don't care

tool/src/org/antlr/v4/semantics/BlankActionSplitterListener.java

@@ -33,24 +33,30 @@ import org.antlr.runtime.Token;
 import org.antlr.v4.parse.ActionSplitterListener;
 
 public class BlankActionSplitterListener implements ActionSplitterListener {
+	@Override
 	public void setQualifiedAttr(String expr, Token x, Token y, Token rhs) {
 	}
 
+	@Override
 	public void qualifiedAttr(String expr, Token x, Token y) {
 	}
 
+	@Override
 	public void setAttr(String expr, Token x, Token rhs) {
 	}
 
+	@Override
 	public void attr(String expr, Token x) {
 	}
 
 	public void templateInstance(String expr) {
 	}
 
+	@Override
 	public void nonLocalAttr(String expr, Token x, Token y) {
 	}
 
+	@Override
 	public void setNonLocalAttr(String expr, Token x, Token y, Token rhs) {
 	}
 
@@ -66,9 +72,11 @@ public class BlankActionSplitterListener implements ActionSplitterListener {
 	public void templateExpr(String expr) {
 	}
 
+	@Override
 	public void unknownSyntax(Token t) {
 	}
 
+	@Override
 	public void text(String text) {
 	}
 }

tool/src/org/antlr/v4/tool/Alternative.java

@@ -77,6 +77,7 @@ public class Alternative implements AttributeResolver {
 
     public Alternative(Rule r, int altNum) { this.rule = r; this.altNum = altNum; }
 
+	@Override
 	public boolean resolvesToToken(String x, ActionAST node) {
 		if ( tokenRefs.get(x)!=null ) return true;
 		LabelElementPair anyLabelDef = getAnyLabelDef(x);
@@ -84,6 +85,7 @@ public class Alternative implements AttributeResolver {
 		return false;
 	}
 
+	@Override
 	public boolean resolvesToAttributeDict(String x, ActionAST node) {
 		if ( resolvesToToken(x, node) ) return true;
         if ( ruleRefs.get(x)!=null ) return true; // rule ref in this alt?
@@ -95,6 +97,7 @@ public class Alternative implements AttributeResolver {
 
 	/**  $x		Attribute: rule arguments, return values, predefined rule prop.
 	 */
+	@Override
 	public Attribute resolveToAttribute(String x, ActionAST node) {
 		return rule.resolveToAttribute(x, node); // reuse that code
 	}
@@ -102,6 +105,7 @@ public class Alternative implements AttributeResolver {
 	/** $x.y, x can be surrounding rule, token/rule/label ref. y is visible
 	 *  attr in that dictionary.  Can't see args on rule refs.
 	 */
+	@Override
 	public Attribute resolveToAttribute(String x, String y, ActionAST node) {
 		if ( rule.name.equals(x) ) { // x is this rule?
 			return rule.resolveToAttribute(x, y, node);
@@ -123,6 +127,7 @@ public class Alternative implements AttributeResolver {
 		return null;
 	}
 
+	@Override
 	public boolean resolvesToLabel(String x, ActionAST node) {
 		LabelElementPair anyLabelDef = getAnyLabelDef(x);
 		return anyLabelDef!=null &&
@@ -130,6 +135,7 @@ public class Alternative implements AttributeResolver {
 				anyLabelDef.type==LabelType.RULE_LABEL);
 	}
 
+	@Override
 	public boolean resolvesToListLabel(String x, ActionAST node) {
 		LabelElementPair anyLabelDef = getAnyLabelDef(x);
 		return anyLabelDef!=null &&

tool/src/org/antlr/v4/tool/Attribute.java

@@ -57,6 +57,7 @@ public class Attribute {
         this.decl = decl;
     }
 
+    @Override
     public String toString() {
         if ( initValue!=null ) {
             return type+" "+name+"="+initValue;

tool/src/org/antlr/v4/tool/AttributeDict.java

@@ -106,6 +106,7 @@ public class AttributeDict {
         return inter;
     }
 
+    @Override
     public String toString() {
         return getName()+":"+attributes;
     }

tool/src/org/antlr/v4/tool/DefaultToolListener.java

@@ -38,6 +38,7 @@ public class DefaultToolListener implements ANTLRToolListener {
 
 	public DefaultToolListener(Tool tool) { this.tool = tool; }
 
+	@Override
 	public void info(String msg) {
 		if (tool.errMgr.formatWantsSingleLineMessage()) {
 			msg = msg.replaceAll("\n", " ");
@@ -45,6 +46,7 @@ public class DefaultToolListener implements ANTLRToolListener {
 		System.out.println(msg);
 	}
 
+	@Override
 	public void error(ANTLRMessage msg) {
 		ST msgST = tool.errMgr.getMessageTemplate(msg);
 		String outputMsg = msgST.render();
@@ -54,6 +56,7 @@ public class DefaultToolListener implements ANTLRToolListener {
 		System.err.println(outputMsg);
 	}
 
+	@Override
 	public void warning(ANTLRMessage msg) {
 		ST msgST = tool.errMgr.getMessageTemplate(msg);
 		String outputMsg = msgST.render();

tool/src/org/antlr/v4/tool/ErrorManager.java

@@ -59,18 +59,22 @@ public class ErrorManager {
 
     STErrorListener theDefaultSTListener =
         new STErrorListener() {
+            @Override
             public void compileTimeError(STMessage msg) {
                 ErrorManager.internalError(msg.toString());
             }
 
+            @Override
             public void runTimeError(STMessage msg) {
                 ErrorManager.internalError(msg.toString());
             }
 
+            @Override
             public void IOError(STMessage msg) {
                 ErrorManager.internalError(msg.toString());
             }
 
+            @Override
             public void internalError(STMessage msg) {
                 ErrorManager.internalError(msg.toString());
             }

tool/src/org/antlr/v4/tool/Grammar.java

@@ -202,7 +202,9 @@ public class Grammar implements AttributeResolver {
 		final Grammar thiz = this;
 		TreeVisitor v = new TreeVisitor(new GrammarASTAdaptor());
 		v.visit(ast, new TreeVisitorAction() {
+			@Override
 			public Object pre(Object t) { ((GrammarAST)t).g = thiz; return t; }
+			@Override
 			public Object post(Object t) { return t; }
 		});
 		initTokenSymbolTables();
@@ -603,21 +605,27 @@ public class Grammar implements AttributeResolver {
 	}
 
 	// no isolated attr at grammar action level
+	@Override
 	public Attribute resolveToAttribute(String x, ActionAST node) {
 		return null;
 	}
 
 	// no $x.y makes sense here
+	@Override
 	public Attribute resolveToAttribute(String x, String y, ActionAST node) {
 		return null;
 	}
 
+	@Override
 	public boolean resolvesToLabel(String x, ActionAST node) { return false; }
 
+	@Override
 	public boolean resolvesToListLabel(String x, ActionAST node) { return false; }
 
+	@Override
 	public boolean resolvesToToken(String x, ActionAST node) { return false; }
 
+	@Override
 	public boolean resolvesToAttributeDict(String x, ActionAST node) {
 		return false;
 	}

tool/src/org/antlr/v4/tool/GrammarTransformPipeline.java

@@ -84,12 +84,14 @@ public class GrammarTransformPipeline {
     public void expandParameterizedLoops(GrammarAST root) {
         TreeVisitor v = new TreeVisitor(new GrammarASTAdaptor());
         v.visit(root, new TreeVisitorAction() {
+            @Override
             public Object pre(Object t) {
                 if ( ((GrammarAST)t).getType() == 3 ) {
                     return expandParameterizedLoop((GrammarAST)t);
                 }
                 return t;
             }
+            @Override
             public Object post(Object t) { return t; }
         });
     }
@@ -104,7 +106,9 @@ public class GrammarTransformPipeline {
 		// ensure each node has pointer to surrounding grammar
 		TreeVisitor v = new TreeVisitor(new GrammarASTAdaptor());
 		v.visit(tree, new TreeVisitorAction() {
+			@Override
 			public Object pre(Object t) { ((GrammarAST)t).g = g; return t; }
+			@Override
 			public Object post(Object t) { return t; }
 		});
 	}

tool/src/org/antlr/v4/tool/LabelElementPair.java

@@ -66,6 +66,7 @@ public class LabelElementPair {
         }
     }
 
+    @Override
     public String toString() {
         return label.getText()+" "+type+" "+element.toString();
     }

tool/src/org/antlr/v4/tool/Rule.java

@@ -233,6 +233,7 @@ public class Rule implements AttributeResolver {
 
 	/**  $x		Attribute: rule arguments, return values, predefined rule prop.
 	 */
+	@Override
 	public Attribute resolveToAttribute(String x, ActionAST node) {
 		if ( args!=null ) {
 			Attribute a = args.get(x);   	if ( a!=null ) return a;
@@ -248,6 +249,7 @@ public class Rule implements AttributeResolver {
 	}
 
 	/** $x.y	Attribute: x is surrounding rule, label ref (in any alts) */
+	@Override
 	public Attribute resolveToAttribute(String x, String y, ActionAST node) {
 		if ( this.name.equals(x) ) { // x is this rule?
 			return resolveToAttribute(y, node);
@@ -265,6 +267,7 @@ public class Rule implements AttributeResolver {
 
 	}
 
+	@Override
 	public boolean resolvesToLabel(String x, ActionAST node) {
 		LabelElementPair anyLabelDef = getAnyLabelDef(x);
 		return anyLabelDef!=null &&
@@ -272,6 +275,7 @@ public class Rule implements AttributeResolver {
 				anyLabelDef.type==LabelType.TOKEN_LABEL);
 	}
 
+	@Override
 	public boolean resolvesToListLabel(String x, ActionAST node) {
 		LabelElementPair anyLabelDef = getAnyLabelDef(x);
 		return anyLabelDef!=null &&
@@ -279,12 +283,14 @@ public class Rule implements AttributeResolver {
 				anyLabelDef.type==LabelType.TOKEN_LIST_LABEL);
 	}
 
+	@Override
 	public boolean resolvesToToken(String x, ActionAST node) {
 		LabelElementPair anyLabelDef = getAnyLabelDef(x);
 		if ( anyLabelDef!=null && anyLabelDef.type==LabelType.TOKEN_LABEL ) return true;
 		return false;
 	}
 
+	@Override
 	public boolean resolvesToAttributeDict(String x, ActionAST node) {
 		if ( resolvesToToken(x, node) ) return true;
 		if ( x.equals(name) ) return true; // $r for action in rule r, $r is a dict

tool/src/org/antlr/v4/tool/ast/GrammarASTErrorNode.java

@@ -42,10 +42,14 @@ public class GrammarASTErrorNode extends GrammarAST {
         delegate = new CommonErrorNode(input,start,stop,e);
     }
 
+    @Override
     public boolean isNil() { return delegate.isNil(); }
 
+    @Override
     public int getType() { return delegate.getType(); }
 
+    @Override
     public String getText() { return delegate.getText(); }
+    @Override
     public String toString() { return delegate.toString(); }
 }

tool/src/org/antlr/v4/tool/interp/LexerInterpreter.java

@@ -58,6 +58,7 @@ public class LexerInterpreter implements TokenSource {
 		this.input = input;
 	}
 
+	@Override
 	public String getSourceName() {	return g.name; }
 
 	@Override
@@ -65,18 +66,22 @@ public class LexerInterpreter implements TokenSource {
 			// TODO: use TokenFactory
 	}
 
+	@Override
 	public int getCharPositionInLine() {
 		return 0;
 	}
 
+	@Override
 	public int getLine() {
 		return 0;
 	}
 
+	@Override
 	public CharStream getInputStream() {
 		return input;
 	}
 
+	@Override
 	public Token nextToken() {
 		// TODO: Deal with off channel tokens
 		int start = input.index();

tool/test/org/antlr/v4/test/ErrorQueue.java

@@ -43,15 +43,18 @@ public class ErrorQueue implements ANTLRToolListener {
 	public List<ANTLRMessage> warnings = new ArrayList<ANTLRMessage>();
     public List<ANTLRMessage> all = new ArrayList<ANTLRMessage>();
 
+	@Override
 	public void info(String msg) {
 		infos.add(msg);
 	}
 
+	@Override
 	public void error(ANTLRMessage msg) {
 		errors.add(msg);
         all.add(msg);
 	}
 
+	@Override
 	public void warning(ANTLRMessage msg) {
 		warnings.add(msg);
         all.add(msg);
@@ -66,6 +69,7 @@ public class ErrorQueue implements ANTLRToolListener {
 		return all.size() + infos.size();
 	}
 
+	@Override
 	public String toString() { return Utils.join(all.iterator(), "\n"); }
 
 	public String toString(Tool tool) {

tool/test/org/antlr/v4/test/TestCommonTokenStream.java

@@ -189,16 +189,21 @@ public class TestCommonTokenStream extends BaseTest {
                     new CommonToken(1,"\n") {{channel = Lexer.HIDDEN;}},
                     new CommonToken(Token.EOF,"")
                 };
+                @Override
                 public Token nextToken() {
                     return tokens[i++];
                 }
+                @Override
                 public String getSourceName() { return "test"; }
+				@Override
 				public int getCharPositionInLine() {
 					return 0;
 				}
+				@Override
 				public int getLine() {
 					return 0;
 				}
+				@Override
 				public CharStream getInputStream() {
 					return null;
 				}