详细讲解JDK内置工具使用技巧(2)

B. 然后我们用jconsole连接到tomcat服务器的java进程，发现基本上Heap size, 垃圾回收都比较正常，但发现tomcat服务器的大部分线程有问题，都处于被Block的状态。
     观察每条线程的stack trace, 发现它们基本上都被堵塞在uk.org.primrose.pool.core.Pool.put和uk.org.primrose.pool.core.Pool.get()的SyncHack同步机制上，我们尝试了改大数据连接池的大小，发现结果是一样的。 

C.这个结论在jstack的结果中同样得到了验证，使用jstack连接到tomcat服务器java进程，并观察结果。

Thread t@38: (state = BLOCKED)

- java.lang.Object.wait(long) @bci=0 (Interpreted frame)
- java.lang.Object.wait(long) @bci=0 (Interpreted frame)
- com._xxx.vportal.common.rpc.session.RemoteServiceGroupFactory.getMaxBalanceFactoryEntry() @bci=165,
line=180 (Interpreted frame)
- com._xxx.vportal.common.rpc.session.RemoteServiceGroupFactory.getService() @bci=80, line=195 (Interpreted
frame)
- com._xxx.vportal.common.rpc.session.RemoteServiceFactory.getSynSender() @bci=1, line=331 (Interpreted
frame)
- com._xxx.vportal.common.rpc.session.RemoteServiceSupport.synRequestHardTask(java.lang.String,
java.lang.Object) @bci=6, line=35 (Interpreted frame)
- com._xxx.vportal.amus.user.client.UserClientRpcImpl.getIconSigner(int, int) @bci=36, line=90 (Interpreted frame)
- net._xxx.forum.model.user.UserInfo.getLogoPath() @bci=109, line=546 (Interpreted frame)
- sun.reflect.GeneratedMethodAccessor13.invoke(java.lang.Object, java.lang.Object[]) @bci=36 (Interpreted frame)
- sun.reflect.DelegatingMethodAccessorImpl.invoke(java.lang.Object, java.lang.Object[]) @bci=6, line=25
(Compiled frame)
- org.apache.velocity.runtime.parser.node.ASTReference.execute(java.lang.Object,
org.apache.velocity.context.InternalContextAdapter) @bci=40, line=207 (Compiled frame)

- org.apache.velocity.runtime.parser.node.ASTBlock.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer) @bci=18, line=94 (Compiled frame)

- org.apache.velocity.runtime.parser.node.SimpleNode.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer) @bci=18, line=271 (Interpreted frame)

-
org.apache.velocity.runtime.parser.node.ASTIfStatement.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer) @bci=63, line=128 (Interpreted frame)

- org.apache.velocity.runtime.parser.node.ASTBlock.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer) @bci=18, line=94 (Compiled frame)

- org.apache.velocity.runtime.directive.Foreach.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer, org.apache.velocity.runtime.parser.node.Node) @bci=95, line=344 (Interpreted frame)

- org.apache.velocity.runtime.parser.node.ASTDirective.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer) @bci=14, line=153 (Interpreted frame)

- org.apache.velocity.runtime.parser.node.SimpleNode.render(org.apache.velocity.context.InternalContextAdapter,
java.io.Writer) @bci=18, line=271 (Interpreted frame)

- org.apache.velocity.app.Velocity.evaluate(org.apache.velocity.context.Context, java.io.Writer, java.lang.String,
java.io.Reader) @bci=102, line=359 (Interpreted frame)

- org.apache.velocity.app.Velocity.evaluate(org.apache.velocity.context.Context, java.io.Writer,
java.lang.String, java.lang.String) @bci=18, line=253 (Interpreted frame)

- net._xxx.forum.util.velocity.VelocityUtil.getVelocityEvaluate(java.util.Map, java.io.Writer,
java.lang.String) @bci=14, line=35 (Interpreted frame)
- net._xxx.forum.action.forum.BbsMessageListAction.go() @bci=1284, line=268 (Interpreted
frame)
–
net._xxx.forum.action.AbstractAction.execute() @bci=1, line=39 (
–
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