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一、首先观察openJDK的的版本

java -version

二、查看openJDK有jmap的yum源

yum whatprovides '*/jmap'

三、选择记得相关的版本进行更新

1:java-1.6.0-openjdk-devel-1.6.0.37-1.13.9.4.el7_1.x86_64 : OpenJDK Development EnvironmentRepo        : updatesMatched from:Filename    : /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.37.x86_64/bin/jmap1:java-1.7.0-openjdk-devel-1.7.0.91-2.6.2.3.el7.x86_64 : OpenJDK Development EnvironmentRepo        : baseMatched from:Filename    : /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64/bin/jmap1:java-1.8.0-openjdk-devel-1.8.0.65-3.b17.el7.x86_64 : OpenJDK Development EnvironmentRepo        : baseMatched from:Filename    : /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64/bin/jmap1:java-1.8.0-openjdk-devel-debug-1.8.0.65-3.b17.el7.x86_64 : OpenJDK Development Environment with full debug onRepo        : baseMatched from:Filename    : /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64-debug/bin/jmap1:java-1.8.0-openjdk-devel-debug-1.8.0.65-3.b17.el7.x86_64 : OpenJDK Development Environment with full debug onRepo        : @baseMatched from:Filename    : /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64-debug/bin/jmap

选择此版本

1:java-1.8.0-openjdk-devel-debug-1.8.0.65-3.b17.el7.x86_64 : OpenJDK Development Environment with full debug on Repo : base Matched from: Filename : /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64-debug/bin/jmap 拷贝加红的jdk进行更新 四、更新jdk、但是有关于JDK服务、需要重新启动。记住必须用root进行更新

yum install java-1.8.0-openjdk-devel-debug-1.8.0.65-3.b17.el7.x86_64

五、进行jmap、jstack、jps操作

jmap -dump:format=b,file=/home/admin/heap.hprof pid pid 是程序的进程号 ps -ef|grep java 就可以查看到jstack  pid > thread.txtjmap -dump:live,format=b,file=heapLive.hprof pid

如果无法dump 说明权限不够不能写入。

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