JDK 8 RFR for JDK-7185456 : (ann) Optimize Annotation handling in java/sun.reflect.* code for small number of annotationsC

[Joe Darcy]

Hello,

Please review this refactoring of how annotations objects are created:
    JDK-7185456 : (ann) Optimize Annotation handling in 
java/sun.reflect.* code for small number of annotationsC
    http://cr.openjdk.java.net/~darcy/7185456.0/

In brief, an annotation object is backed by a hash map with one entry 
per method defined on the annotation type. Currently the default HashMap 
constructor which uses a default capacity of 16 is used. Since most 
annotation type define many fewer methods, some space is wasted. The 
patch (inline below) "right sizes" the HashMap to match the number of 
methods in the annotation type.

Thanks,

-Joe

--- old/src/share/classes/sun/reflect/annotation/AnnotationType.java 
2013-03-26 15:37:22.000000000 -0700
+++ new/src/share/classes/sun/reflect/annotation/AnnotationType.java 
2013-03-26 15:37:22.000000000 -0700
@@ -45,19 +45,18 @@
      * types.  This matches the return value that must be used for a
      * dynamic proxy, allowing for a simple isInstance test.
      */
-    private final Map<String, Class<?>> memberTypes = new 
HashMap<String,Class<?>>();
+    private final Map<String, Class<?>> memberTypes;

     /**
      * Member name -> default value mapping.
      */
-    private final Map<String, Object> memberDefaults =
-        new HashMap<String, Object>();
+    private final Map<String, Object> memberDefaults;

     /**
      * Member name -> Method object mapping. This (and its assoicated
      * accessor) are used only to generate 
AnnotationTypeMismatchExceptions.
      */
-    private final Map<String, Method> members = new HashMap<String, 
Method>();
+    private final Map<String, Method> members;

     /**
      * The retention policy for this annotation type.
@@ -105,6 +104,9 @@
                 }
             });

+        memberTypes = new HashMap<String,Class<?>>(methods.length+1, 1.0f);
+        memberDefaults = new HashMap<String, Object>(0);
+        members = new HashMap<String, Method>(methods.length+1, 1.0f);

         for (Method method :  methods) {
             if (method.getParameterTypes().length != 0)