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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 ZeroTurnaround. Check out this 8-step guide to see how you can increase your productivity by skipping slow application redeploys and by implementing application profiling, as you code!

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