#fixed code
                                @Override
    public boolean putConfigIfAbsent(String dataId, String content, long timeoutMills) {
        ConfigFuture configFuture = new ConfigFuture(dataId, content, ConfigFuture.ConfigOperation.PUTIFABSENT, timeoutMills);
        consulNotifierExecutor.execute(() -> {
            PutParams putParams = new PutParams();
            //Setting CAS to 0 means that this is an atomic operation, created when key does not exist.
            putParams.setCas(CAS);
            complete(getConsulClient().setKVValue(dataId, content, putParams), configFuture);
        });
        return (Boolean) configFuture.get();
    }
#vulnerable code 
                                @Override
    public boolean putConfigIfAbsent(String dataId, String content, long timeoutMills) {
        ConfigFuture configFuture = new ConfigFuture(dataId, content, ConfigFuture.ConfigOperation.PUTIFABSENT, timeoutMills);
        consulConfigExecutor.execute(() -> {
            PutParams putParams = new PutParams();
            //Setting CAS to 0 means that this is an atomic operation, created when key does not exist.
            putParams.setCas(CAS);
            complete(getConsulClient().setKVValue(dataId, content, putParams), configFuture);
        });
        return (Boolean) configFuture.get();
    } 
                            #location 4 
                            #vulnerability type THREAD_SAFETY_VIOLATION