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Thomas Enebo Releases JMX Gem

· Java Zone

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I wrote a JMX client library quite a while back and I finally got around to putting it on jruby-extras. To get the magic you can:
jruby -S gem install jmx

Once you have it you can do things like:
require 'jmx'

server = JMX.simple_server
client = JMX.connect
memory = client["java.lang:type=Memory"]

puts memory.heap_memory_usage.used
memory.gc
puts memory.heap_memory_usage.used

server.stop

Or even construct your own MBean from within Ruby code:

class MyDynamicMBean < RubyDynamicMBean
operation "Doubles a value"
parameter :int, "a", "Value to double"
returns :int
def double(a)
a + a
end
end
[see jmx/test/jmx_server_test.rb for details on how to register]

This library is still a little rough around the edges, but I have used it to great utility for debugging permgen memory issues. Charlie also recently just committed some MBeans for monitoring the JIT statistics (along with a way to flush the JIT cache). This client should be helpful for us to write some nice Ruby-friendly scripts to analyze a running instance.

Have fun and if you have questions come onto our IRC channel (#jruby at irc.freenode.net) or send an email to one of our mailing lists.

The Java Zone is brought to you in partnership with JetBrains.  Learn about instant and clever code completion, on-the-fly code analysis and reliable refactoring tools with IntelliJ IDEA.

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