How to increase heap memory of your java application in Eclipse

Question

can anyone teach me how to increase your heap size using arguments like -Xms1024m -Xmx1024m ? What is the difference of Program argument and VM argument?

Solution 1

If you go to Run -> Run Configuration in the Arguments Tab you will find the VM Arguments section where you can add this.

Sample Entry in VM Arguments

-Xms50M -Xmx128M

In Program Arguments you mention the arguments which will be passed to the Main Class.

Solution 2

Go to the eclipse.ini file in Eclipse directory.

 -startup
plugins/org.eclipse.equinox.launcher_1.3.0.v20130225-1645.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.200.v20130228-0336
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-vmargs
-Xms1152m
-Xmx1152m

and change

**openFile
    -vmargs
    -Xms1152m
    -Xmx1152m**

accordingly.

Comments

[Enrico]

So which argument will be carried by the jar file? I'm wondering if the jar I am creating retains this max values i set in these argument

[Ajay George]

@user2655077 There will be none which will be retained in the jar file that you create.To run your jar you need to pass these params from cmd line. java -Xms50M -Xmx128M -jar yourjar.jar

[Ajay George]

OP is not asking about increasing eclipse's memory.

[Enrico]

I think I'm enlightened by that @Ajay George.. ^^

[Master]

Yes but sometimes you need to, to run large apps on Eclipse. To change it simply go to your eclipse directory and change in eclipse.ini it should work definitely.

[Enrico]

now my problem is how much memory should i allocate to my app? The server where this app is running has 32G memory..

[Ajay George]

@user2655077 that would be a very difficult question to answer without knowing more about your app. Why don't you start by giving it 1G and see whether that suffices.

[Enrico]

i have allocated 2 gb and after few seconds it throws OOM

[Ajay George]

try bumping it up to 4 G and enable -XX:-HeapDumpOnOutOfMemoryError to get the heap dump. Use it to analyze which objects are taking up most memory.