Java – use request Getsession () as the lock object?

I have some java code to get and set a session property:

Object obj = session.getAttribute(TEST_ATTR);
if (obj==null) {
  obj = new MyObject();
  session.setAttribute(obj);
}

To make this code thread safe, I want to wrap it in synchronized blocks But what do I use as a lock object? Does it make sense to use the session?

synchronized (session) {
  Object obj = session.getAttribute(TEST_ATTR);
  if (obj==null) {
    obj = new MyObject();
    session.setAttribute(obj);
  }
}

Solution

Usually frown and use locks you can't control The lock should be locked as tightly as possible. Since the session is more or less a global object, it does not comply with the bill Try using a separate lock from Java util. concurrent. Locks the package and ranges it to your class