Skip to main content

Using JConsole in java And creating memory dump by it.

Starting jconsole


The jconsole executable is in JDK_HOME/bin, where JDK_HOME is the directory where the JDK is installed.  If this directory is on your system path, you can start the tool by simply typing jconsole in a command (shell) prompt. Otherwise, you have to type the full path to the executable file


Now run the jconsole exe from cmd.




you will get a new window and it will ask to select a java exe to examine.


After selecting the java process you will get a window with the overview of the process





In upper tabs you can find the more options such as thread here you can find the number of theards and its memory.



On memory tab you will get more option to to view different memories.





You can also see the overview of the whole process



Now to create heap dump we have to enter the path at first parameter and true in second. Once we get a heap dump we can analyse it with different tools . In my next post i will explain hoe to analyse it with  Memory Analyzer (MAT) - Eclipse

You may also like:-

How to Reduce Garbage-Collection Pause Time?

4 Mains causes of Long Garbage Collection Pause?

How Application Performance get impacted by Garbage Collection?

Java Performance Tuning options Java heap

Why Memory leak in Java ?

What is a Memory Leak in java?

What is Garbage collector in java and how it works?

What is Garbage Collector Compaction in Java?

What are Java heap Young, Old and Permanent Generations?

What is difference between Web Server and Application Server ?

What is the maximum ram for 32 bits and 64 bits computer?

Popular posts from this blog

What are Java heap Young, Old and Permanent Generations?

The Java heap is dived into two parts i.e. Young generation and old generation. Young generationYoung generation  memory is 40% of Maximum Java Heap. It consists of two parts, Eden space and Survivor Space. Eden SpaceInitially objects are created in this  Part of Java Heap , here most objects die and quickly are cleaned up by the minor Garbage Collectors (It only runs in young generation and its frequency is high in compared to major garbage collector). Usually any new objects created inside a Java Method go into Eden space and the objects space is reclaimed once the method execution completes. Whereas the Instance Variables of a Class usually lives longer until the Object based on that class gets destroyed. When Eden fills up it causes a minor collection, in which some surviving objects are moved to Survivor Space or an older generation. Survivor Space  The pool containing objects that have survived the garbage collection of the Eden space The parameter Survivor Ratio can be used to tune…

Compression of HttpServletRequest and HttpServletResponse by gzip encoding

Description 
This filter is on HTTP headers in a HttpServletRequest, compress data written to the HttpServletResponse, or decompress data read from the request. When supported by the client browser, this can potentially greatly reduce the number of bytes written across the network from and to the client. As a Filter, this class can also be easily added to any J2EE 1.3+ web application.





Installation

1).Add the pjl-comp-filter-XX.jar file containing CompressingFilter to your web application's WEB-INF/lib directory.

2).Add the following entries to your web.xml deployment descriptor:

 <filter>
  <filter-name>CompressingFilter</filter-name>
  <filter-class>com.planetj.servlet.filter.compression.CompressingFilter</filter-class>
 </filter>

 <filter-mapping>
  <filter-name>CompressingFilter</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>

The below data is of my application where i tested this compression technique…

4 mains causes of Long Garbage Collection Pause?

So a long GC Pause can have a direct impact on response time and throughput. But there are some causes for long GC pause which you can check and avoid to increase performance. They are as follows:-


1)Insufficient heap size:- If heap size is small then the size required then the allocation requests for new objects  fail and the JVM needs to invoke garbage collections in an attempt to reclaim space for the allocations. So these frequent Full GCs cause long pauses in the application run. To avoid long GC pause by this identify the average footprint of the application and then specify the heap size accordingly.
2)Fragmentation in the heap:-GCs can occur more frequently due to fragmentation in the Java Heap  and also sometimes causing long pauses in the GCs. This is more probable in the case of Concurrent Mark Sweep collector, also known as CMS, where the tenured generation space is not compacted with the concurrent collections. For more please go through the previous post about heap  compact…