src/share/classes/sun/reflect/generics/tree/BottomSignature.java

@@ -26,11 +26,11 @@
 package sun.reflect.generics.tree;
 
 import sun.reflect.generics.visitor.TypeTreeVisitor;
 
 public class BottomSignature implements FieldTypeSignature {
-    private static BottomSignature singleton = new BottomSignature();
+    private static final BottomSignature singleton = new BottomSignature();
 
     private BottomSignature(){}
 
     public static BottomSignature make() {return singleton;}