你如何从壳牌强制垃圾收集？ [英] How do you Force Garbage Collection from the Shell?

问题描述

所以我在一个远程盒子上查看一个带有jmap的堆，我想强制垃圾收集。你如何做到这一点，而不会弹出到jvisualvm或jconsole和朋友？

So I am looking at a heap with jmap on a remote box and I want to force garbage collection on it. How do you do this without popping into jvisualvm or jconsole and friends?

我知道你不应该在强制垃圾收集的做法 - 你应该弄清楚为什么堆很大/越来越大。

I know you shouldn't be in the practice of forcing garbage collection -- you should just figure out why the heap is big/growing.

我也意识到System.GC（）实际上并不强制垃圾收集 - 它只是告诉GC你会喜欢它的发生。

I also realize the System.GC() doesn't actually force garbage collection -- it just tells the GC that you'd like it to occur.

说了这么简单吗？我缺少一些命令行应用程序？

Having said that is there a way to do this easily? Some command line app I'm missing?

推荐答案

您可以通过免费的 jmxterm 程序。

You can do this via the free jmxterm program.

启动它：

java -jar jmxterm-1.0-alpha-4-uber.jar

从那里，您可以连接到主机并触发GC：

From there, you can connect to a host and trigger GC:

$>open host:jmxport
#Connection to host:jmxport is opened
$>bean java.lang:type=Memory
#bean is set to java.lang:type=Memory
$>run gc
#calling operation gc of mbean java.lang:type=Memory
#operation returns: 
null
$>quit
#bye

查看jmxterm网站上的文档，获取有关将其嵌入到bash / perl / ruby​​ / other脚本。我在Python中使用了popen2或者在Perl中使用了open3。

Look at the docs on the jmxterm web site for information about embedding this in bash/perl/ruby/other scripts. I've used popen2 in Python or open3 in Perl to do this.

UPDATE：这里是使用jmxterm的单线程：

UPDATE: here's a one-liner using jmxterm:

echo run -b java.lang:type=Memory gc | java -jar jmxterm-1.0-alpha-4-uber.jar -n -l host:port

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