[HDFS-14923] Remove dead code from HealthMonitor

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.3.0, 3.2.1, 3.1.3
• Fix Version/s: 3.3.0, 3.1.4, 3.2.2
• Assignee: Hui Fei
• Reporter: Hui Fei
• Created: 23/Oct/19 12:13
• Updated: 25/Oct/19 22:21
• Resolved: 25/Oct/19 22:07

Description

Dig ZKFC source code and find that the dead code as follow

public void removeCallback(Callback cb) {
   callbacks.remove(cb);
}

public synchronized void removeServiceStateCallback(ServiceStateCallback cb) {
   serviceStateCallbacks.remove(cb);
}

synchronized HAServiceStatus getLastServiceStatus() {
   return lastServiceState;
}

It's useless, and should be deleted.