add @Override to hush warnings. Manually did some of https://github.com/antlr/antlr4/pull/1066

runtime/Java/src/org/antlr/v4/runtime/tree/xpath/XPath.java

@@ -85,6 +85,7 @@ public class XPath {
 			throw new IllegalArgumentException("Could not read path: "+path, ioe);
 		}
 		XPathLexer lexer = new XPathLexer(in) {
+			@Override
 			public void recover(LexerNoViableAltException e) { throw e;	}
 		};
 		lexer.removeErrorListeners();

tool/src/org/antlr/v4/codegen/target/JavaScriptTarget.java

@@ -220,14 +220,17 @@ public class JavaScriptTarget extends Target {
 
 	}
 
+	@Override
 	public boolean wantsBaseListener() {
 		return false;
 	}
 
+	@Override
 	public boolean wantsBaseVisitor() {
 		return false;
 	}
 
+	@Override
 	public boolean supportsOverloadedMethods() {
 		return false;
 	}

tool/src/org/antlr/v4/gui/TreeViewer.java

@@ -393,6 +393,7 @@ public class TreeViewer extends JComponent {
 
 		// make viz
         WindowListener exitListener = new WindowAdapter() {
+	        @Override
             public void windowClosing(WindowEvent e) {
                 prefs.putInt(DIALOG_WIDTH_PREFS_KEY, (int) dialog.getSize().getWidth());
                 prefs.putInt(DIALOG_HEIGHT_PREFS_KEY, (int) dialog.getSize().getHeight());