#vulnerable code 
                                private void initialize() {
        boolean isDone = false;
        Exception lastException = null;

        for (int i = 0; (!isDone) && (i < MAX_INITIALIZATION_ATTEMPTS); i++) {
            try {
                LOG.info("Initialization attempt " + (i + 1));
                LOG.info("Initializing LeaseCoordinator");
                leaseCoordinator.initialize();

                LOG.info("Syncing Kinesis shard info");
                ShardSyncTask shardSyncTask =
                        new ShardSyncTask(streamConfig.getStreamProxy(),
                                leaseCoordinator.getLeaseManager(),
                                initialPosition,
                                cleanupLeasesUponShardCompletion,
                                0L);
                TaskResult result = new MetricsCollectingTaskDecorator(shardSyncTask, metricsFactory).call();

                if (result.getException() == null) {
                    if (!leaseCoordinator.isRunning()) {
                        LOG.info("Starting LeaseCoordinator");
                        leaseCoordinator.start();
                    } else {
                        LOG.info("LeaseCoordinator is already running. No need to start it.");
                    }
                    isDone = true;
                } else {
                    lastException = result.getException();
                }
            } catch (LeasingException e) {
                LOG.error("Caught exception when initializing LeaseCoordinator", e);
                lastException = e;
            } catch (Exception e) {
                lastException = e;
            }

            try {
                Thread.sleep(parentShardPollIntervalMillis);
            } catch (InterruptedException e) {
                LOG.debug("Sleep interrupted while initializing worker.");
            }
        }

        if (!isDone) {
            throw new RuntimeException(lastException);
        }
    } 
                            #location 20 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                private void initialize() {
        boolean isDone = false;
        Exception lastException = null;

        for (int i = 0; (!isDone) && (i < MAX_INITIALIZATION_ATTEMPTS); i++) {
            try {
                LOG.info("Initialization attempt " + (i + 1));
                LOG.info("Initializing LeaseCoordinator");
                leaseCoordinator.initialize();

                TaskResult result = null;
                if (!skipShardSyncAtWorkerInitializationIfLeasesExist
                        || leaseCoordinator.getLeaseManager().isLeaseTableEmpty()) {
                    LOG.info("Syncing Kinesis shard info");
                    ShardSyncTask shardSyncTask =
                            new ShardSyncTask(streamConfig.getStreamProxy(),
                                    leaseCoordinator.getLeaseManager(),
                                    initialPosition,
                                    cleanupLeasesUponShardCompletion,
                                    0L);
                    result = new MetricsCollectingTaskDecorator(shardSyncTask, metricsFactory).call();
                } else {
                    LOG.info("Skipping shard sync per config setting (and lease table is not empty)");
                }

                if (result == null || result.getException() == null) {
                    if (!leaseCoordinator.isRunning()) {
                        LOG.info("Starting LeaseCoordinator");
                        leaseCoordinator.start();
                    } else {
                        LOG.info("LeaseCoordinator is already running. No need to start it.");
                    }
                    isDone = true;
                } else {
                    lastException = result.getException();
                }
            } catch (LeasingException e) {
                LOG.error("Caught exception when initializing LeaseCoordinator", e);
                lastException = e;
            } catch (Exception e) {
                lastException = e;
            }

            try {
                Thread.sleep(parentShardPollIntervalMillis);
            } catch (InterruptedException e) {
                LOG.debug("Sleep interrupted while initializing worker.");
            }
        }

        if (!isDone) {
            throw new RuntimeException(lastException);
        }
    }