decompiler: support java 9 bytecode version

src/org/jetbrains/java/decompiler/code/CodeConstants.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@ public interface CodeConstants {
   int BYTECODE_JAVA_6 = 3;
   int BYTECODE_JAVA_7 = 4;
   int BYTECODE_JAVA_8 = 5;
+  int BYTECODE_JAVA_9 = 6;
 
   // ----------------------------------------------------------------------
   // VARIABLE TYPES

src/org/jetbrains/java/decompiler/struct/StructClass.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -180,6 +180,8 @@ public class StructClass extends StructMember {
 
   public int getBytecodeVersion() {
     switch (majorVersion) {
+      case 53:
+        return CodeConstants.BYTECODE_JAVA_9;
       case 52:
         return CodeConstants.BYTECODE_JAVA_8;
       case 51: