Java 线程卡住

问：

代码为：

//=========
//classA
//=========
private static final int CORE_POOL_SIZE = Math.max(1, Runtime.getRuntime().availableProcessors() / 2);
private static final int MAX_POOL_SIZE = CORE_POOL_SIZE + 1;
private static final int KEEP_ALIVE_TIME = 60;
private static final int MAX_QUEUE_SIZE = 100000;
private ThreadPoolExecutor pool = new ThreadPoolExecutor(CORE_POOL_SIZE, MAX_POOL_SIZE, KEEP_ALIVE_TIME, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(MAX_QUEUE_SIZE));

public void addTask(final String md5) {
    pool.submit(() -> {
        try {
            logger.info("a1");
            doAction(md5);
            logger.info("a2");
        } catch (Exception e) {
            logger.error("a3");
        }
    });
}

private void doAction(final String md5) throws Exception {
    logger.error("b1");
    saveFile(getFileByMd5(md5), md5);
    logger.error("b2");
}

public void saveFile(final File file, final String md5) throws Exception {
    synchronized (md5.intern()) {
        log.info("c1");
        FileAttUtils.parseFileInfo(file);
        log.info("c2");
    }
}

//=========
//classB
//=========
public class FileAttUtils {
    public static Map<String, Object> parseFileInfo(File file) {
        log.info("d1");
        SimpleImageInfo image = new SimpleImageInfo(file.getAbsolutePath());
        log.info("d2");
    }
}

//=========
//classC
//=========
public class SimpleImageInfo { 
  
  public SimpleImageInfo(String path) {
    String suffix = getFileSuffix(path);
    log.info("e1");
    InputStream is = null;
    try {
      ...
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      ...
    } 
  }
  
  private static String getFileSuffix(String path) {
    String result = null;
    if (path != null) {
      result = "";
      if (path.lastIndexOf('.') != -1) {
        result = path.substring(path.lastIndexOf('.'));
        if (result.startsWith("."))
          result = result.substring(1); 
      } 
    } 
    log.info("getFileSuffix: {}", result);
    return result;
  }
  
}

在程序中调用时，将显示以下内容：addTasklog

[pool-2-thread-1] xxxxx: a1
[pool-2-thread-2] xxxxx: a1
[pool-2-thread-1] xxxxx: b1
[pool-2-thread-2] xxxxx: b1
[pool-2-thread-1] xxxxx: c1
[pool-2-thread-2] xxxxx: c1
[pool-2-thread-1] xxxxx: d1
[pool-2-thread-2] xxxxx: d1

该程序似乎卡在这一行：

SimpleImageInfo image = new SimpleImageInfo(file.getAbsolutePath());

但从日志来看，程序似乎根本没有进入（因为没有打印）SimpleImageInfo#constructore1

我观察到以下两条线程消息：jstack

"pool-2-thread-2" #56 prio=5 os_prio=0 tid=0x00007fb6dc003000 nid=0x4e54 waiting on condition [0x00007fb754fe4000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x00000006c1931ae8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
        at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
        at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:748)

   Locked ownable synchronizers:
        - None

"pool-2-thread-1" #55 prio=5 os_prio=0 tid=0x00007fb6dc002000 nid=0x4e53 waiting on condition [0x00007fb75fe51000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x00000006c1931ae8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
        at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
        at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:748)

   Locked ownable synchronizers:
        - None

我搜索了 的所有输出，但我找不到线程（停车等待<0x00000006c1931ae8>）。jstack0x00000006c1931ae8

我想知道为什么我的程序卡住了？为什么线程中的代码在执行中途进入等待状态？