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Example of MemoryUsage in Java

By Arvind Rai, March 25, 2013
MemoryUsage class belongs to the package java.lang.management. MemoryUsage provides the snapshot of memory usage. Object of MemoryUsage is returned by the methods of MemoryPoolMXBean. MemoryUsage gives the information like amount of memory that can be used by java virtual machine. MemoryUsage gives the information of current use of memory by virtual machine etc.
MemoryUsageTest.java
package com.concretepage;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryPoolMXBean;
import java.lang.management.MemoryUsage;
import java.util.List;
public class MemoryUsageTest {
  class UserThread extends Thread {
      public void run() {
              //using getMemoryPoolMXBeans
              System.out.println("result of getMemoryPoolMXBeans ");
              List<MemoryPoolMXBean> mpmxList = ManagementFactory.getMemoryPoolMXBeans();
              for (MemoryPoolMXBean pl : mpmxList) {
                String name=pl.getName();
                System.out.println(name);
                MemoryUsage mu = pl.getPeakUsage();
                System.out.println("---using MemoryUsage---");
                // memory that can be used by JVM
                System.out.println(mu.getCommitted());
                // memory that is being used by JVM
                System.out.println(mu.getUsed());  
                //memory which has been request initially.
                System.out.println(mu.getInit());
                //max memory that can be requested.
                System.out.println(mu.getMax());
              }
      }
  }
  public static void main(String[] a){
      Thread th= new MemoryUsageTest().new UserThread();
      Runtime.getRuntime().addShutdownHook(th);
  }
}
Output
result of getMemoryPoolMXBeans 
Code Cache
---using MemoryUsage---
2555904
382208
2555904
50331648
PS Eden Space
---using MemoryUsage---
32899072
1974088
32899072
689569792
PS Survivor Space
---using MemoryUsage---
5439488
0
5439488
5439488
PS Old Gen
---using MemoryUsage---
87556096
0
87556096
1400897536
PS Perm Gen
---using MemoryUsage---
21757952
2762360
21757952
85983232 
POSTED BY
ARVIND RAI
ARVIND RAI
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