Fix possible NPE while editing ANTLR Grammar
diff --git a/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v3/Antlr3ParserResult.java b/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v3/Antlr3ParserResult.java
index cdd29cd..84c7583 100644
--- a/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v3/Antlr3ParserResult.java
+++ b/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v3/Antlr3ParserResult.java
@@ -137,8 +137,11 @@
 
             @Override
             public void exitRule_(ANTLRv3Parser.Rule_Context ctx) {
-                AntlrStructureItem.RuleStructureItem rule = new AntlrStructureItem.RuleStructureItem(ctx.id_().getText(), getFileObject(), ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex() + 1);
-                structure.add(rule);
+                if (ctx.id_() != null) {
+                    AntlrStructureItem.RuleStructureItem rule = new AntlrStructureItem.RuleStructureItem(
+                            ctx.id_().getText(), getFileObject(), ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex() + 1);
+                    structure.add(rule);
+                }
             }
 
         };
diff --git a/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v4/Antlr4ParserResult.java b/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v4/Antlr4ParserResult.java
index eba55a4..ffffb31 100644
--- a/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v4/Antlr4ParserResult.java
+++ b/java/languages.antlr/src/org/netbeans/modules/languages/antlr/v4/Antlr4ParserResult.java
@@ -211,7 +211,7 @@
 
             @Override
             public void exitLexerRuleSpec(ANTLRv4Parser.LexerRuleSpecContext ctx) {
-                if (ctx.FRAGMENT() == null) {
+                if ((ctx.FRAGMENT() == null) && (ctx.TOKEN_REF() != null)) {
                     // Do not represent fragments in the structure
                     AntlrStructureItem.RuleStructureItem rule = new AntlrStructureItem.RuleStructureItem(ctx.TOKEN_REF().getText(), getFileObject(), ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex() + 1);
                     lexerStructure.add(rule);
@@ -220,8 +220,10 @@
 
             @Override
             public void exitParserRuleSpec(ANTLRv4Parser.ParserRuleSpecContext ctx) {
-                AntlrStructureItem.RuleStructureItem rule = new AntlrStructureItem.RuleStructureItem(ctx.RULE_REF().getText(), getFileObject(), ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex() + 1);
-                structure.add(rule);
+                if (ctx.RULE_REF() != null) {
+                    AntlrStructureItem.RuleStructureItem rule = new AntlrStructureItem.RuleStructureItem(ctx.RULE_REF().getText(), getFileObject(), ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex() + 1);
+                    structure.add(rule);
+                }
             }
 
             @Override