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This article will explain in detail how to analyze the javacore of was with jca tools. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

A friend called for help and asked how to analyze WAS's JAVACORE file simply and conveniently. I did an example analysis for him, and here is a record of the process.

I. tool download

The JCA tool, which is specifically used to analyze JAVACORE files, can be downloaded from the IBM official website. The JAVA environment is required to use the JCA tool, so download another JDK. Since we are using version 3.9.6 of JCA, just download a version of JDK1.6.

Start the JCA tool

After installing JDK1.6, configure the JAVA environment. The configuration of the JAVA environment can be described briefly:

Turn on my computer-- Properties-- Advanced-- Environment variables

New system variables JAVA_HOME and CLASSPATH

Variable name: JAVA_HOME

Variable value: C:\ Program Files\ Java\ 1.6.0room37

Variable name: CLASSPATH

Variable value:.;% JAVA_HOME%\ lib\ dt.jar;%JAVA_HOME%\ lib\ tools.jar

Select the environment variable named "Path" in the "system variable", double-click the variable, add the absolute path of the bin directory in the JDK installation path to the value of the Path variable, and separate the semicolon of the half corner from the existing path.

Variable name: Path

Variable value: C:\ Program Files\ Java\ 1.6.0room37\ bin;C:\ Program Files\ Java\ 1.6.0room37\ jre\ bin

Start the JCA tool

C:\ jca396 > java-Xmx2000M-jar jca396.jar

Error occurred during initialization of VM

Could not reserve enough space for object heap

Could not create the Java virtual machine.

If this error occurs, just make the memory allocation smaller.

C:\ jca396 > java-Xmx500M-jar jca396.jar javacore.20131101.txt

Click on the events with more waiting status, which are shown as follows

This is a typical BLOCK stowage, and there are corresponding reference articles on the official website of IBM. A relatively simple way to solve this problem is to increase the JVM size of WAS.

Third, solve the problem

Go to the WAS console, find the JVM settings, and adjust them. As shown in the figure:

Server-application server-app01-- process definition-Java virtual machine

Note: when the application deployed on websphere has problems, such as slow call, thread suspension, and node fake death, it is not enough to look at the SystemOut.log of the application, we also need to generate the javacore file manually to query the stack of each thread on the server, which can be specific to the call of a method. Javacore is the text representation of a Java application at some point in time, and it can also be understood as a thread dump file of Java Dump (often referred to as Thread Dump). This file records the operation of the entire JVM, including thread, garbage collection, JVM running parameters, memory address and other information. Many problems with JVM can be diagnosed with this file, typical of which include thread blocking, high CPU utilization, JVM Crash, insufficient heap memory, and class loading.

Javacore files are usually displayed in the form of * .txt, and the name format mainly takes Javacore as the header, plus the date number, the generated time number, and the current thread number.

Generation of Javacore files

Ps-ef | grep java view the process ID, which uses kill-3 pid on the linux system, which generates a javacore file in the directory of the application's profile, such as under / usr/IBM/WebSphere/AppServer1/profiles/AppSrv01.

On the jca tool how to analyze was javacore to share here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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