How to check how much memory is used by a program??

[Pooja Patole]

Hello ,

I want to check how much memory is available before runny a piece of code and how much is available afterwards. What function do i need to use??.


Pooja

[Eshwin Sukhdeve]

1) to get the maximum amount of memory that your Java application can use:
Runtime runtime = Runtime.getRuntime();
System.out.println("max memory: " + runtime.maxMemory() / 1024);

2)to get how much memory that JVM has allocated for your application
Runtime runtime = Runtime.getRuntime();
System.out.println("allocated memory: " + runtime.totalMemory() / 1024);

3)to get how much memory is being used by your application:
Runtime runtime = Runtime.getRuntime();
System.out.println("free memory: " + runtime.freeMemory() / 1024);

[John Jai]

I think you can use Runtime class' totalMemory() and freeMemory() to compute your program's usability of JVM provided your program is only executed in that JVM.

[John Jai]

Eshwin Sukhdeve wrote:to get how much memory is being used by your application:

If other programs are being executed in the same JVM, it might include the usage of other programs too right?

[Pooja Patole]

Thank you John and Eshwin ..

[Eshwin Sukhdeve]

good question john.I am not sure..but i think it will include..because this function will give the available memory allocation...so it should check
how much free memory is there.

[Jesper de Jong]

John Jai wrote:If other programs are being executed in the same JVM, it might include the usage of other programs too right?

Normally, a JVM is executing only one program. If you start two Java programs on your computer, there will be two separate JVMs executing the two programs.

A good tool to monitor what Java programs are doing is VisualVM. It's included with Java 6 and newer. Type jvisualvm in a command prompt window to start it.

[Pooja Patole]

Hi,

I want to use MemoryUsage methods to check how much memory is being used.. How can i do that???

Pooja

[chirag pandav]

Hello

we have syntax for finding  memory allocation for whole program (we can use -:Runtime.getRuntime().totalMemory())

but my question is -:
public class temp9 {

   public void Method1 () {
       for (int i = 0; i < 30000; i++) {
           System.out.print("");
       }
   }

how much memory that METHOD1 will take , while we execute this code.. is there any way to find it?

Thanks in advance

[Stephan van Hulst]

Welcome to CodeRanch!

You can use a profiler to find out that kind of information. Most IDEs have a decent one built in.