#vulnerable code 
                                public void push(String item) throws IOException {
        if (getRun() == null) {
            LOGGER.warning("run is null, cannot push");
            return;
        }
        synchronized (getRun()) {
            BulkChange bc = new BulkChange(getRun());
            try {
                AbstractInvisibleRunAction2 action = getRun().getAction(AbstractInvisibleRunAction2.class);
                if (action == null) {
                    action = new AbstractInvisibleRunAction2(getRun());
                    getRun().addAction(action);
                }
                action.stack.push(item);
                bc.commit();
            } finally {
                bc.abort();
            }
        }
    } 
                            #location 6 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public void push(String item) throws IOException {
        if (run == null) {
            LOGGER.warning("run is null, cannot push");
            return;
        }
        synchronized (run) {
            BulkChange bc = new BulkChange(run);
            try {
                AbstractInvisibleRunAction2 action = run.getAction(this.getClass());
                if (action == null) {
                    action = createAction(run);
                    run.addAction(action);
                }
                LOGGER.log(Level.INFO, "Pushing item {0} to action {1} in run {2}", new Object[] { item, action, run });
                action.stack.push(item);
                bc.commit();
            } finally {
                bc.abort();
            }
        }
    }