BlockingQueue.take（）迭代中的java.util.ConcurrentModificationException

Question

我有一个ConcurrentHashmap，它被多个线程更新。

ConcurrentHashMap<String, BlockingQueue<StateObject>> querystatestore = new ConcurrentHashMap<String, BlockingQueue<StateObject>>();

当线程之一尝试从某个阻塞队列中提取对象并尝试处理该对象时，它会在迭代后抛出 java.util.ConcurrentModificationException 。 从Blockingqueue读取的代码段是

public class ExecuteMatcher implements Runnable {

	public BlockingQueue<StateObject> state;
	public String queryname;

	/**
	 * @param state
	 * @param queryname
	 */
	public ExecuteMatcher(BlockingQueue<StateObject> state, String queryname) {
		super();
		this.state = state;
		this.queryname = queryname;

	}

	public void executematcher(BlockingQueue<StateObject> state1, String queryname2) {

		// need to add poison pill else the loop willl never end....
		while (true) {

			StateObject object;
			try {
				object = state1.take();
				if (object != null) {
					// Thread.sleep(100);
					printstate(object);
					// Thread.sleep(100);

				}

			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

		}

	}

	public static void printstate(StateObject state1) {

		for (PublicationGraphEvent ge : state1.getState()) {
			for (VertexObject vertex : ge.getPubGraph().vertexSet()) {
				System.out.println("When STate fetehed from blocking queue: " + vertex.getVertex_label()
						+ "  Vertex_id:  " + vertex.getVertex_id() + "Eventid: " + ge.getEventID());
			}

		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Runnable#run()
	 */
	@Override
	public void run() {
		// TODO Auto-generated method stub

		this.executematcher(state, queryname);

	}

}

这是在for循环中发生的，而迭代是 for（PublicationGraphEvent ge：state1.getState（））的。我不明白为什么我的清单会被更新。有什么方法可以停止 state1.take（）; 功能，直到本方法完成，以便我可以从队列中取出另一个对象来处理它。在这一点上，我真的很挣扎，任何帮助将不胜感激。