JDK自带命令jstack通过JVM堆栈分析出现大量线程的原因

xuqinglei · Feb 23, 2017 · 247959f · 247959f
1 parent c44c367
commit 247959f
Showing 1 changed file with 17 additions and 6 deletions.
diff --git a/Java_jstack/README.md b/Java_jstack/README.md
@@ -4,18 +4,26 @@
 首先找到JVM进程
 
 	[root@10-13-40-54 social-search]# ps -aux | grep tomcat
-	root      7437  5.8  8.0 10049732 1303772 pts/0 Sl  09:31   1:12 /usr/bin/java -Djava.util.logging.config.file=/usr/local/5080SocialSearchTomcat/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/usr/local/5080SocialSearchTomcat/endorsed -classpath /usr/local/5080SocialSearchTomcat/bin/bootstrap.jar:/usr/local/5080SocialSearchTomcat/bin/tomcat-juli.jar -Dcatalina.base=/usr/local/5080SocialSearchTomcat -Dcatalina.home=/usr/local/5080SocialSearchTomcat -Djava.io.tmpdir=/usr/local/5080SocialSearchTomcat/temp org.apache.catalina.startup.Bootstrap start
+	root      7437  5.8  8.0 10049732 1303772 pts/0 Sl  09:31   
+	1:12 /usr/bin/java -Djava.util.logging.config.file=/usr/local/5080SocialSearchTomcat/conf/
+	logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=
+	/usr/local/5080SocialSearchTomcat/endorsed -classpath /usr/local/5080SocialSearchTomcat/bin/bootstrap.jar:
+	/usr/local/5080SocialSearchTomcat/bin/tomcat-juli.jar -Dcatalina.base=/usr/local/5080SocialSearchTomcat 
+	 -Dcatalina.home=/usr/local/5080SocialSearchTomcat -Djava.io.tmpdir=/usr/local/5080SocialSearchTomcat/
+	temp/org.apache.catalina.startup.Bootstrap start
 
 得到JVM的tomcat进程是7437，然后把堆栈导出，下载到本地：
 
 	jstack -l 7437 > log.txt
 
 下载后，发现线程堆栈中，有大量的这样的日志：
 
-	"pool-2918-thread-2" #14663 prio=5 os_prio=0 tid=0x00007fdc81759000 nid=0x157c waiting on condition [0x00007fd8821ef000]
+	"pool-2918-thread-2" #14663 prio=5 os_prio=0 tid=0x00007fdc81759000 nid=0x157c 
+	waiting on condition [0x00007fd8821ef000]
 	   java.lang.Thread.State: WAITING (parking)
 		at sun.misc.Unsafe.park(Native Method)
-		- parking to wait for  <0x000000079329da40> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
+		- parking to wait for  <0x000000079329da40
+			- > - (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
 		at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
 		at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
 		at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
@@ -24,10 +32,12 @@
 		at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 		at java.lang.Thread.run(Thread.java:745)
 
-	"pool-2918-thread-1" #14662 prio=5 os_prio=0 tid=0x00007fdc81757000 nid=0x157b waiting on condition [0x00007fd8822f0000]
+	"pool-2918-thread-1" #14662 prio=5 os_prio=0 tid=0x00007fdc81757000 nid=0x157b 
+	waiting on condition [0x00007fd8822f0000]
 	   java.lang.Thread.State: WAITING (parking)
 		at sun.misc.Unsafe.park(Native Method)
-		- parking to wait for  <0x000000079329da40> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
+		- parking to wait for  <0x000000079329da40> 
+			- (a java.util.concurrent.locks.AbstractQueuedSynchronizer$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)
@@ -42,7 +52,8 @@
 
 补充下LinkedBlockingQueue的知识：
 
-	>并发库中的BlockingQueue是一个比较好玩的类，顾名思义，就是阻塞队列。该类主要提供了两个方法put()和take()，前者将一个对象放到队列尾部，
+	>并发库中的BlockingQueue是一个比较好玩的类，顾名思义，就是阻塞队列。该类主要提供了两个方法put()和take()，
+	>前者将一个对象放到队列尾部，
 	>如果队列已经满了，就等待直到有空闲节点；后者从head取一个对象，如果没有对象，就等待直到有可取的对象。
 
 定位到问题就简单了，查找代码，发现有个位置启动了线程池提交了任务，但是任务执行完返回后，线程池没有关闭导致的；