JDK 13 RFR of JDK-8042748: Clarify exception thrown by ParameterizedTypeImpl.validateConstructorArguments()

[Joe Darcy]

Hello,

Please review the patch below to address

     JDK-8042748: Clarify exception thrown by 
ParameterizedTypeImpl.validateConstructorArguments()

Thanks,

-Joe

diff -r 0a7af38ef32a 
src/java.base/share/classes/sun/reflect/generics/reflectiveObjects/ParameterizedTypeImpl.java
--- 
a/src/java.base/share/classes/sun/reflect/generics/reflectiveObjects/ParameterizedTypeImpl.java 
Thu Jun 06 17:48:06 2019 -0700
+++ 
b/src/java.base/share/classes/sun/reflect/generics/reflectiveObjects/ParameterizedTypeImpl.java 
Thu Jun 06 18:52:14 2019 -0700
@@ -56,7 +56,14 @@
          TypeVariable<?>[] formals = rawType.getTypeParameters();
          // check correct arity of actual type args
          if (formals.length != actualTypeArguments.length){
-            throw new MalformedParameterizedTypeException();
+            throw new 
MalformedParameterizedTypeException(String.format("Mismatch of count of " +
+                                    "formal and actual type " +
+                                    "arguments in constructor " +
+                                    "of %s: %d formal argument(s) "+
+                                    "%d actual argument(s)",
+                                    rawType.getName(),
+                                    formals.length,
+ actualTypeArguments.length));
          }
          for (int i = 0; i < actualTypeArguments.length; i++) {
              // check actuals against formals' bounds