Method isJavaThread

src/vmStructs.h:401–406

This thread is considered a JavaThread if at least 2 of the selected 3 vtable entries match those of a known JavaThread (which is either application thread or AttachListener). Indexes were carefully chosen to work on OpenJDK 8 to 25, both product an debug builds.

    // match those of a known JavaThread (which is either application thread or AttachListener).
    // Indexes were carefully chosen to work on OpenJDK 8 to 25, both product an debug builds.
    bool isJavaThread() {
        const void** vtbl = vtable();
        return (vtbl[1] == _java_thread_vtbl[1]) +
               (vtbl[3] == _java_thread_vtbl[3]) +
               (vtbl[5] == _java_thread_vtbl[5]) >= 2;
    }

    int state() {
        return _thread_state_offset >= 0 ? *(int*) at(_thread_state_offset) : 0;