RFR 8056900: Enhance NoClassDefFound exception messaging

[David Holmes]

Hi Harold,

On 3/05/2017 4:29 AM, harold seigel wrote:
> Hi,
>
> Please review this small JDK-10 change to enhance NoClassDefFoundError
> exception messages.
>
> Open Webrev:
> http://cr.openjdk.java.net/~hseigel/bug_8056900/webrev/index.html

A few comments:

In src/share/vm/oops/instanceKlass.cpp

517     // This is for CDS dumping phase only -- we use the 
in_error_state to indicate that
518     // the class has failed verification.

That comment is somewhat misleading. The is_in_error_state() indicates 
that class initialization failed, not verification. However CDS dumping 
also uses it to indicate if a supertype was is_in_error_state(). I think 
using:

527                        "Verification failed for class %s",

would be confusing to an end user trying to figure out how a perfectly 
valid class could fail verification! I suggest the more direct:

"Class %s, or one of its supertypes, failed class initialization"

---

src/share/vm/prims/jni.cpp

Suggestion:

"Class name exceeds maximum length of %d: %s", ...

in both cases.

386     THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), "Class 
name is null");

Suggestion: "No class name given"

---

Ditto for src/share/vm/prims/jvm.cpp changes.

---

Thanks,
David
-----


> JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8056900
>
> The change was tested with JCK tests, the JTreg hotspot, java/io,
> java/lang, java/util and other tests, the RBT tier2 -tier5 tests, the
> co-located NSK tests, JPRT, and with the new test provided with the change.
>
> Thanks, Harold
>