Java dynamically list allocated objects

Question

I'm searching a way to find a list of allocated objects inside the JVM.

I don't want to use a profiler as I want to see these object during runtime, inside the code itself. I wanna create a graph of all objects present inside the program and the interactions between each others.

Do you have a start of a way? I already searched for lots of reflection classes and profilers example but couldn't find something relevant for my case.

Thank you in advance

Answer 1

You could achieve this with JVMTI. GetLoadedClasses function is a good entry point

JavaVM *jvm;
jvmtiEnv *jvmti;
jvmtiError err;

env->GetJavaVM(&jvm);
jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_2);

jint classCount = 0;
jclass * classes;

// get all classes loaded by jvm
jvmti->GetLoadedClasses(&classCount, &classes);

You can also traverse heap and thus build a graph of objects.

Answer 2

Do you have a start of a way?

Yes, you can take a heap dump and analyse the heap dump.

Note: use a heap analyser which already exists would be simplest. e.g. visualvm, An application can have many millions of objects so a tool designed to do this will help you navigate the data.