From: Jeremy Manson <jeremymanson@google.com> Subject: Crash with TraceClassLoading Date: 19 december 2013 21:01:02 CET To: "hotspot-runtime-dev@openjdk.java.net" <hotspot-runtime-dev@openjdk.java.net> Now that 9 is underway, presumably we can start feeding back fixes again. This one's a bit obscure. TraceClassLoading expects there to be a (Java) caller when you load a class with the bootstrap class loader. However, there are ways of loading a class that don't involve having a Java caller. For example, you can do so from a JVMTI hook. A reproduction is attached, and here's a patch: diff --git a/src/share/vm/classfile/classFileParser.cpp b/src/share/vm/classfile/classFileParser.cpp --- a/src/share/vm/classfile/classFileParser.cpp +++ b/src/share/vm/classfile/classFileParser.cpp @@ -4098,8 +4098,12 @@ tty->print("[Loaded %s from %s]\n", this_klass->external_name(), cfs->source()); } else if (class_loader.is_null()) { - if (THREAD->is_Java_thread()) { - Klass* caller = ((JavaThread*)THREAD)->security_get_caller_class(1); + Klass* caller = + THREAD->is_Java_thread() + ? ((JavaThread*)THREAD)->security_get_caller_class(1) + : NULL; + // caller can be NULL, for example, during a JVMTI VM_Init hook + if (caller != NULL) { tty->print("[Loaded %s by instance of %s]\n", this_klass->external_name(), InstanceKlass::cast(caller)->external_name()); Jeremy