8230626: Make UnknownFooException strings more informative

Reviewed-by: jjg, mr

Author: jddarcy

src/java.compiler/share/classes/javax/lang/model/element/UnknownAnnotationValueException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -60,7 +60,7 @@ public class UnknownAnnotationValueException extends UnknownEntityException {
      * @param p an additional parameter, may be {@code null}
      */
     public UnknownAnnotationValueException(AnnotationValue av, Object p) {
-        super("Unknown annotation value: " + av);
+        super("Unknown annotation value: \"" + av + "\"");
         this.av = av;
         this.parameter = p;
     }

src/java.compiler/share/classes/javax/lang/model/element/UnknownElementException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,7 +58,7 @@ public class UnknownElementException extends UnknownEntityException {
      * @param p an additional parameter, may be {@code null}
      */
     public UnknownElementException(Element e, Object p) {
-        super("Unknown element: " + e);
+        super("Unknown element: \"" + e + "\"");
         element = e;
         this.parameter = p;
     }

src/java.compiler/share/classes/javax/lang/model/type/UnknownTypeException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,7 +58,7 @@ public class UnknownTypeException extends UnknownEntityException {
      * @param p an additional parameter, may be {@code null}
      */
     public UnknownTypeException(TypeMirror t, Object p) {
-        super("Unknown type: " + t);
+        super("Unknown type: \"" + t + "\"");
         type = t;
         this.parameter = p;
     }