??????? ? Java SE 6

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??????? ? Java SE 6

• Monitoring and Management

Mihail Stoynovmihail.stoynov.com
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Demo

• Java Process Status Tool
• jps

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C\gt JConsole
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JConsole

• Dynamic Attach
• You can connect to every process started in Java
  SE 6 HotSpot VM (through Attach API)
• No more -Dcom.sun.management.jmxremote on every
  application (Management Agent)
• Remote monitoring
• Can be password protected
• Secure remote monitoring (SSL)

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JConsole

• Can follow memory
• Can see stack trace, thread state
• Can see VM summary
• Can detect deadlocks
• Can see all the MBeans from JMX
• Can be used to detect warn for low memory
• Can tell CPU usage
• Can save all

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Demo

• A simple application seen through JConsole, jstack

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Demo

• Remote monitoring using JConsole

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Heap Histogram

• Finding memomy leaks
• C\gtjmap -histo 3328
• See how much instances every class has
• See how much memory instances occupy
• Can filter only live objects in the heap
• Can save to a binary file format
• JConsole can do that through an JMX Mbean
• Can read with jhat

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Demo

• Saving using JConsole

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Heap Histogram on OutOfMemoryError

• jinfo flag HeapDumpOnOutMemoryError ltpidgt
• ...
• java.lang.OutOfMemoryError Java heap spaceDump
  heap to java_pid1412.hprof ...Heap dump file
  created 68354173 bytes in 4.416 secs Exception
  in thread "main" java.lang.OutOfMemoryError Java
  heap space
• ...
• C\gtjhat java_pid1412.hprof

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Thank you

• Monitoring and Management

Mihail Stoynovmihail.stoynov.com