java.lang.Thread - threadStatus来自哪里？

Question

通过Java源代码我们有

// variable not written or updated anywhere on this class
private volatile int threadStatus = 0;

public State getState() {
    // get current thread state
    return sun.misc.VM.toThreadState(threadStatus);
}

如何以及在何处threadStatus更新？

我们的想法是最终尝试使用AOP编写更新方法,并对threadStatus更改进行回调.

Answer 1

在OpenJDK文件中的源代码中,hotspot/src/share/vm/classfile/javaClasses.cpp您可以看到以下代码:

// Write the thread status value to threadStatus field in java.lang.Thread java class.
void java_lang_Thread::set_thread_status(oop java_thread,
                                         java_lang_Thread::ThreadStatus status) {
  // The threadStatus is only present starting in 1.5
  if (_thread_status_offset > 0) {
    java_thread->int_field_put(_thread_status_offset, status);
  }
}

看起来状态是用本机代码管理的.这意味着您无法从java代码中拦截其更改.