终止java CLI时neo4j驱动程序出现问题

最近我将（org.neo4j.driver）

neo4jjava驱动程序

从

1.4.4

升级到最新的

1.7.5

，因为我想开始在db中使用时态类型。升级后，在我开始使用CLI工具（在我的代码中准备的自定义工具）之前，所有这些工具似乎都工作得很顺利，当它们终止时，就会陷入无休止的循环：

Warning: unterminated thread Neo4jDriverIO-2-10 [23] [sun.nio.ch.EPollArrayWrapper.epollWait(Native Method), sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269), sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93), sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86), sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97), org.neo4j.driver.internal.shaded.io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:753), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:409), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
WARNING: Warning: unterminated thread Neo4jDriverIO-2-10[sun.nio.ch.EPollArrayWrapper.epollWait(Native Method), sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269), sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93), sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86), sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97), org.neo4j.driver.internal.shaded.io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:753), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:409), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
Warning: unterminated thread Neo4jDriverIO-2-9 [22] [sun.nio.ch.EPollArrayWrapper.epollWait(Native Method), sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269), sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93), sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86), sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97), org.neo4j.driver.internal.shaded.io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:753), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:409), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
WARNING: Warning: unterminated thread Neo4jDriverIO-2-9[sun.nio.ch.EPollArrayWrapper.epollWait(Native Method), sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269), sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93), sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86), sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97), org.neo4j.driver.internal.shaded.io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:753), org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:409), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
[..]

在退出CLI程序之前，我尝试直接调用驱动程序上的close（）方法。当程序结束时，它起了一点作用，但我仍然可以看到以下堆栈：

INFO: Closing driver instance 1162128198
Nov 14, 2019 5:03:25 PM org.neo4j.driver.internal.logging.JULogger info
INFO: Closing connection pool towards neo4j:7687
Warning: unterminated thread globalEventExecutor-1-2 [36] [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078), java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.GlobalEventExecutor.takeTask(GlobalEventExecutor.java:92), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.GlobalEventExecutor$TaskRunner.run(GlobalEventExecutor.java:245), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
WARNING: Warning: unterminated thread globalEventExecutor-1-2[sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078), java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.GlobalEventExecutor.takeTask(GlobalEventExecutor.java:92), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.GlobalEventExecutor$TaskRunner.run(GlobalEventExecutor.java:245), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
Warning: unterminated thread globalEventExecutor-1-2 [36] [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078), java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.GlobalEventExecutor.takeTask(GlobalEventExecutor.java:92), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.GlobalEventExecutor$TaskRunner.run(GlobalEventExecutor.java:245), org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30), java.lang.Thread.run(Thread.java:748)]
[..] 

你知道为什么它不能正常关闭（或者为什么它会产生网状的线程？）以及为什么我会看到这样的堆栈吗

注:

• 当然，在1.4.4的情况下，未观察到此类问题
• 我使用直接螺栓连接到外部单个neo4j db实例

更新

所以我找到了我看到这些日志的原因。基本上，Neo4jDriverIO线程现在是守护进程线程，我的CLI代码一直在检查是否有任何线程.isDaemon为true，并一直在等待这些线程关闭

在第一种情况下，它们永远不会关闭，因为neo4j驱动程序中的.close（）方法应该由JVM关闭钩子调用，而JVM关闭钩子从来不会像我们在这个isDaemon循环中那样出现

仍然是第二个问题，为什么globalEventExecutor-1-2在close（）方法期间不关闭，而只是在一段时间后关闭（这意味着它们以异步方式关闭）。这可能是一个错误，但会挖掘更多