原文：
Dump文件分析
本文主要介绍Dump文件结构，理解Dump文件对于分析线程高占用、死锁、内存溢出等高级问题有非常重要的指导意义。
什么是Dump文件
Dump文件是进程的内存镜像。可以把程序的执行状态通过调试器保存到dump文件中。
Dump文件是用来给程序编写人员调试程序用的，这种文件必须用专用工具软件打开。
如何生成Dump文件
使用命令：jstack pid
可以查看到当前运行的java进程的dump信息。
Dump文件结构
首先浏览一下dump文件的文本内容：
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.77-b03 mixed mode):
"Attach Listener" #37 daemon prio=9 os_prio=0 tid=0x00007f87b42b7000 nid=0x680f waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"Druid-ConnectionPool-Destory-331358539" #36 daemon prio=5 os_prio=0 tid=0x00007f87a4278800 nid=0x67e4 waiting on condition [0x00007f87b8dce000]
java.lang.Thread.State: TIMED_WAITING (sleeping)
at java.lang.Thread.sleep(Native Method)
at com.alibaba.druid.pool.DruidDataSource$DestroyConnectionThread.run(DruidDataSource.java:1724)
"Druid-ConnectionPool-Create-331358539" #35 daemon prio=5 os_prio=0 tid=0x00007f87a4022000 nid=0x67e3 waiting on condition [0x00007f87ce86a000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000b3804848> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:1629)
"Abandoned connection cleanup thread" #31 daemon prio=5 os_prio=0 tid=0x00007f87e0d91800 nid=0x672b in Object.wait() [0x00007f87cd2c2000]
java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
- locked <0x00000000b422d1e8> (a java.lang.ref.ReferenceQueue$Lock)
at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:43)
"DestroyJavaVM" #30 prio=5 os_prio=0 tid=0x00007f87e0008800 nid=0x670b waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"http-nio-8081-AsyncTimeout" #28 daemon prio=5 os_prio=0 tid=0x00007f87e016e800 nid=0x6727 waiting on condition [0x00007f87b94cf000]
java.lang.Thread.State: TIMED_WAITING (sleeping)
at java.lang.Thread.sleep(Native Method)
at org.apache.coyote.AbstractProtocol$AsyncTimeout.run(AbstractProtocol.java:1211)
at java.lang.Thread.run(Thread.java:745)
"http-nio-8081-Acceptor-0" #27 daemon prio=5 os_prio=0 tid=0x00007f87e0166000 nid=0x6726 runnable [0x00007f87b95d0000]
java.lang.Thread.State: RUNNABLE
at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
- locked <0x00000000b410d480> (a java.lang.Object)
at org.apache.tomcat.util.net.NioEndpoint$Acceptor.run(NioEndpoint.java:455)
at java.lang.Thread.run(Thread.java:745)
"http-nio-8081-ClientPoller-0" #26 daemon prio=5 os_prio=0 tid=0x00007f87e0292800 nid=0x6725 runnable [0x00007f87b96d1000]
java.lang.Thread.State: RUNNABLE
at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
- locked <0x00000000b410d6c0> (a sun.nio.ch.Util$2)
- locked <0x00000000b410d6b0> (a java.util.Collections$UnmodifiableSet)
- locked <0x00000000b410d668> (a sun.nio.ch.EPollSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:793)
at java.lang.Thread.run(Thread.java:745)
"http-nio-8081-exec-10" #25 daemon prio=5 os_prio=0 tid=0x00007f87e028c000 nid=0x6724 waiting on condition [0x00007f87b97d2000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000b410d898> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$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 org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103)
at org.apache.tomcat