In process JVMDI and -Xdebug option

Question

Hi
I have coded a JVMPI module which wants to make use of JVMDI HotSwap feature and only that one. So I am using an "in process JVMDI".
I am wondering if there is a mean to run the VM with my module and not necessary with -Xdebug to use redefineClass method of JVMDI API, since I am not interested in getting the JVMDI events notifications and suspending facilities.
If I start my jvm with
java -XrunMyModule -Xdebug ...
it works fine.
If I start my jvm with
java -XrunMyModule ...
it fails under a jdk 1.4.2 during MyModule JVM_OnLoad with the following code returning an jvmdiError -3
JVMDI_Interface_1 *jvmdi;
jint res = jvm->GetEnv((void**)&jvmdi, JVMDI_VERSION_1);
if (res < 0) {
fprintf(stderr, "MyModule> JVMDI prepare failed [code %d]\n", res);
Since -3 is a JNI_EVERSION code, and not a JVMDI_ERROR_ACCESS_DENIED, I am rather surprised.
Thanks
Alex

Answer 1

Hello
You wrote:
If I start my jvm with
java -XrunMyModule -Xdebug ...
it works fine.
If I start my jvm with
java -XrunMyModule ...
it fails under a jdk 1.4.2 during MyModule JVM_OnLoad
with the following code returning an jvmdiError -3
JVMDI_Interface_1 *jvmdi;
jint res = jvm->GetEnv((void**)&jvmdi,
, JVMDI_VERSION_1);
if (res < 0) {
fprintf(stderr, "MyModule> JVMDI prepare failed
led [code %d]\n", res);
}Having "-Xdebug" on the command line causes the VM
to do bare bones JVMDI initialization at startup time.
It is required. Without that initialization it is fatal
to try to use the interface later.
Since -3 is a JNI_EVERSION code, and not a
JVMDI_ERROR_ACCESS_DENIED, I am rather surprised.JNI_EVERSION means the version is not supported which isn't
true here, but there is no other error code we can return.