Program: 130778
Project: 130778
Buggy source:
/** 
 * Begins executing leader steps. It returns if any exception is caught, which causes it goes back to election phase.
 */
void lead(){
  ExecutorService es=Executors.newCachedThreadPool(DaemonThreadFactory.FACTORY);
  try {
    MDC.put("String_Node_Str","String_Node_Str");
    LOG.debug("String_Node_Str");
    if (stateChangeCallback != null) {
      stateChangeCallback.leaderDiscovering(config.getServerId());
    }
    if (failCallback != null) {
      failCallback.leaderDiscovering();
    }
    getPropsedEpochFromQuorum();
    proposeNewEpoch();
    waitEpochAckFromQuorum();
    LOG.debug("String_Node_Str",getProposedEpochFromFile());
    String serverId=selectSyncHistoryOwner();
    LOG.debug("String_Node_Str",serverId);
    MDC.put("String_Node_Str","String_Node_Str");
    LOG.debug("String_Node_Str");
    if (stateChangeCallback != null) {
      stateChangeCallback.leaderSynchronizating(getProposedEpochFromFile());
    }
    if (failCallback != null) {
      failCallback.leaderSynchronizing();
    }
    if (!serverId.equals(this.config.getServerId())) {
      synchronizeFromFollower(serverId);
    }
    setAckEpoch(getProposedEpochFromFile());
    beginSynchronizing(es);
    waitNewLeaderAckFromQuorum();
    this.currentState=ZabState.LEADING;
    MDC.put("String_Node_Str","String_Node_Str");
    LOG.debug("String_Node_Str");
    if (failCallback != null) {
      failCallback.leaderBroadcasting();
    }
    if (stateChangeCallback != null) {
      stateChangeCallback.leaderBroadcasting(getAckEpochFromFile(),getAllTxns());
    }
    beginBroadcasting(es);
  }
 catch (  InterruptedException|TimeoutException|IOException|RuntimeException e) {
    LOG.error("String_Node_Str",e);
    for (    PeerHandler ph : this.quorumSet.values()) {
      ph.shutdown();
      this.quorumSet.remove(ph.getServerId());
    }
    es.shutdown();
  }
}

Fixed version (ground truth):
/** 
 * Begins executing leader steps. It returns if any exception is caught, which causes it goes back to election phase.
 * @throws InterruptedException in case of interrupted.
 */
void lead() throws Exception {
  ExecutorService es=Executors.newCachedThreadPool(DaemonThreadFactory.FACTORY);
  try {
    MDC.put("String_Node_Str","String_Node_Str");
    LOG.debug("String_Node_Str");
    if (stateChangeCallback != null) {
      stateChangeCallback.leaderDiscovering(config.getServerId());
    }
    if (failCallback != null) {
      failCallback.leaderDiscovering();
    }
    getPropsedEpochFromQuorum();
    proposeNewEpoch();
    waitEpochAckFromQuorum();
    LOG.debug("String_Node_Str",getProposedEpochFromFile());
    String serverId=selectSyncHistoryOwner();
    LOG.debug("String_Node_Str",serverId);
    MDC.put("String_Node_Str","String_Node_Str");
    LOG.debug("String_Node_Str");
    if (stateChangeCallback != null) {
      stateChangeCallback.leaderSynchronizating(getProposedEpochFromFile());
    }
    if (failCallback != null) {
      failCallback.leaderSynchronizing();
    }
    if (!serverId.equals(this.config.getServerId())) {
      synchronizeFromFollower(serverId);
    }
    setAckEpoch(getProposedEpochFromFile());
    beginSynchronizing(es);
    waitNewLeaderAckFromQuorum();
    this.currentState=ZabState.LEADING;
    MDC.put("String_Node_Str","String_Node_Str");
    LOG.debug("String_Node_Str");
    if (failCallback != null) {
      failCallback.leaderBroadcasting();
    }
    if (stateChangeCallback != null) {
      stateChangeCallback.leaderBroadcasting(getAckEpochFromFile(),getAllTxns());
    }
    beginBroadcasting(es);
  }
 catch (  InterruptedException|TimeoutException|IOException|RuntimeException e) {
    LOG.error("String_Node_Str",e);
    for (    PeerHandler ph : this.quorumSet.values()) {
      ph.shutdown();
      this.quorumSet.remove(ph.getServerId());
    }
    es.shutdown();
    if (e instanceof InterruptedException) {
      throw (InterruptedException)e;
    }
  }
}