Ivan Popov wrote:
Working on HARMONY-3304 [1] I noticed problem with JNI function NewGlobalRef() in DRLVM. If it is called for a pending exception object before ExceptionClear() is invoked, it returns NULL, which is interpreted as out of memory according to JNI spec [2]. This causes errors in debug support. In Sun/BEA VM non-NULL reference is returned in this case.
Actually JNI specification [1] states that only 3 JNI functions may be safely called in exception state. Looking at the code of NewGloabRef I see that the check for exception was added at revision 489694 as a result of committing HARMONY-2817.
Simple workaround is to call ExceptionClear() before NewGlobalRef(). However, I'm not sure if ExceptionClear() won't dispose exception
ExceptionClear zeroes a reference to exception object in TLS which is considered as no exception state. The object itself may be collected later if there are no live references to it left.
object itself. To my mind it's better to fix NewGlobalRef() and make it compatible with RI.
[1] http://java.sun.com/j2se/1.5.0/docs/guide/jni/spec/design.html#wp17626 -- Gregory
