#vulnerable code 
                                public void commit(long zxid) {
        lastCommitted = zxid;
        QuorumPacket qp = new QuorumPacket(Leader.COMMIT, zxid, null, null);
        sendPacket(qp);
               
        if(pendingSyncs.containsKey(zxid)){
            sendSync(syncHandler.get(pendingSyncs.get(zxid).sessionId), pendingSyncs.get(zxid));
            syncHandler.remove(pendingSyncs.get(zxid));
            pendingSyncs.remove(zxid);
        }
    } 
                            #location 7 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void commit(long zxid) {
        lastCommitted = zxid;
        QuorumPacket qp = new QuorumPacket(Leader.COMMIT, zxid, null, null);
        sendPacket(qp);
    }