[8u] RFR JDK-8161144: Fix for JDK-8147451 failed: Crash in Method::checked_resolve_jmethod_id(_jmethodID*)

[Shafi Ahmad]

Hi,

Please review the small code change for bug: "JDK-8161144: Fix for JDK-8147451 failed: Crash in Method::checked_resolve_jmethod_id(_jmethodID*)" on jdk8u-dev

Summary:
Method::deallocate_contents() should clear 'this' from list of Methods in JNIMethodBlock, similarly to clear_all_methods() does it, when class is unloaded.  
After this change I am seeing Method::is_method_id() is getting called with NULL and I have done below change to avoid crash 

-  assert(m != NULL, "should be called with non-null method");
+  if (m == NULL) {
+    return false;
+  }

Webrev: http://cr.openjdk.java.net/~shshahma/8161144/webrev/
Jdk8 bug: https://bugs.openjdk.java.net/browse/JDK-8161144

Test:  Run jprt

Regards,
Shafi