Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Using the Java Runtime API for JVM Memory Details

DZone's Guide to

Using the Java Runtime API for JVM Memory Details

· Java Zone ·
Free Resource

Bring content to any platform with the open-source BloomReach CMS. Try for free.

Reading runtime information about Java is useful when your application is struggling to get resources. System Memory is one of the main resources that an application developer has to consider while managing the application. Hence sometimes it is beneficial to see what amount of memory your application using and what amount of free memory is in system.

Java’s Runtime class provides lot of information about the resource details of Java Virtual Machine or JVM. The memory consumed by the JVM can be read by different methods in Runtime class.

The following is a small example of getting/reading JVM Heap Size, Total Memory and used memory using Java Runtime API.

/**
* Class: TestMemory
* @author: Viral Patel
* @description: Prints JVM memory utilization statistics
*/
public class TestMemory {

public static void main(String [] args) {

int mb = 1024*1024;

//Getting the runtime reference from system
Runtime runtime = Runtime.getRuntime();

System.out.println("##### Heap utilization statistics [MB] #####");

//Print used memory
System.out.println("Used Memory:"
+ (runtime.totalMemory() - runtime.freeMemory()) / mb);

//Print free memory
System.out.println("Free Memory:"
+ runtime.freeMemory() / mb);

//Print total available memory
System.out.println("Total Memory:" + runtime.totalMemory() / mb);

//Print Maximum available memory
System.out.println("Max Memory:" + runtime.maxMemory() / mb);
}
}

You may also want to print the memory utilization in Kilobytes KBs. For that just assign 1024 value to the int variable mb.

From http://viralpatel.net/blogs

BloomReach CMS: the API-first CMS of the future. Open-source & enterprise-grade. - As a Java developer, you will feel at home using Maven builds and your favorite IDE (e.g. Eclipse or IntelliJ) and continuous integration server (e.g. Jenkins). Manage your Java objects using Spring Framework, write your templates in JSP or Freemarker. Try for free.

Topics:

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}