Java 多线程技巧

版权声明：欢迎转载，转载请说明出处. 大数据Github项目地址https://github.com/SeanYanxml/bigdata。 https://blog.csdn.net/u010416101/article/details/88756889

总结

本章主要记录.Java多线程分析和使用过程中的一些技巧.后续的内容也会陆续补充在此处.

---

正文

1. 如何Dump文件?
   使用jstack -l <pid> >> filename. 例如: jstack -l 20866 > hello.log
   参考
   如何分析Thread Dump（收集）
   Dump文件
   JAVA dump查看线程运行情况

2019-03-22 10:41:05
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.102-b14 mixed mode):

"Attach Listener" #24434 daemon prio=9 os_prio=31 tid=0x00007fe56bd78800 nid=0x335b waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
	- None

"org.apache.hadoop.fs.FileSystem$Statistics$StatisticsDataReferenceCleaner" #11 daemon prio=5 os_prio=31 tid=0x00007fe56bdb1800 nid=0x3a07 in Object.wait() [0x0000700005d00000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0x0000000781b23218> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
	- locked <0x0000000781b23218> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
	at org.apache.hadoop.fs.FileSystem$Statistics$StatisticsDataReferenceCleaner.run(FileSystem.java:3061)
	at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
	- None

"Service Thread" #8 daemon prio=9 os_prio=31 tid=0x00007fe56b030000 nid=0x4503 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
	- None

"C1 CompilerThread2" #7 daemon prio=9 os_prio=31 tid=0x00007fe56c001000 nid=0x4603 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
	- None

"C2 CompilerThread1" #6 daemon prio=9 os_prio=31 tid=0x00007fe56b02f800 nid=0x3703 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
	- None

"C2 CompilerThread0" #5 daemon prio=9 os_prio=31 tid=0x00007fe56b871000 nid=0x3603 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
	- None

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007fe56b878800 nid=0x4903 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
	- None

"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007fe56c000000 nid=0x3003 in Object.wait() [0x00007000055eb000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
	- locked <0x000000078183b2d0> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
	at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

   Locked ownable synchronizers:
	- None

"Reference Handler" #2 daemon prio=10 os_prio=31 tid=0x00007fe56b010000 nid=0x5103 in Object.wait() [0x00007000054e8000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	at java.lang.Object.wait(Object.java:502)
	at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
	- locked <0x000000078183b310> (a java.lang.ref.Reference$Lock)
	at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

   Locked ownable synchronizers:
	- None

"main" #1 prio=5 os_prio=31 tid=0x00007fe56b005000 nid=0x1c03 waiting on condition [0x0000700004ed6000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
	at java.lang.Thread.sleep(Native Method)
	at org.apache.hadoop.mapreduce.v2.hs.HistoryFileManager.createHistoryDirs(HistoryFileManager.java:586)
	at org.apache.hadoop.mapreduce.v2.hs.HistoryFileManager.serviceInit(HistoryFileManager.java:552)
	at org.apache.hadoop.service.AbstractService.init(AbstractService.java:163)
	- locked <0x0000000781b23ae0> (a java.lang.Object)
	at org.apache.hadoop.mapreduce.v2.hs.JobHistory.serviceInit(JobHistory.java:94)
	at org.apache.hadoop.service.AbstractService.init(AbstractService.java:163)
	- locked <0x0000000781853c20> (a java.lang.Object)
	at org.apache.hadoop.service.CompositeService.serviceInit(CompositeService.java:107)
	at org.apache.hadoop.mapreduce.v2.hs.JobHistoryServer.serviceInit(JobHistoryServer.java:143)
	at org.apache.hadoop.service.AbstractService.init(AbstractService.java:163)
	- locked <0x0000000781853cb8> (a java.lang.Object)
	at org.apache.hadoop.mapreduce.v2.hs.JobHistoryServer.launchJobHistoryServer(JobHistoryServer.java:221)
	at org.apache.hadoop.mapreduce.v2.hs.JobHistoryServer.main(JobHistoryServer.java:231)

   Locked ownable synchronizers:
	- None

"VM Thread" os_prio=31 tid=0x00007fe56b868800 nid=0x5203 runnable

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007fe56b816800 nid=0x2007 runnable

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007fe56b817800 nid=0x2a03 runnable

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007fe56b818000 nid=0x2b03 runnable

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007fe56b818800 nid=0x5303 runnable

"VM Periodic Task Thread" os_prio=31 tid=0x00007fe56b01c800 nid=0x4303 waiting on condition

JNI global references: 267