Fix NPE when there are no parameter annotations.

git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@247 30ef5769-5b8d-40dd-aea6-55b5d6557bb3

src/main/javassist/CtClassType.java

         int numParameters = 0;
         if (a1 != null) 
             numParameters = a1.numParameters();
-        else
+        else if (a2 != null)
             numParameters = a2.numParameters();
+        else
+           return new Object[0][];
 
         Object[][] result = new Object[numParameters][];
         ClassLoader cl = Thread.currentThread().getContextClassLoader();