How to increase the java heap size in netbeans?

Question

I am trying to build a lexicon trie of almost 110000 words in java in netbeans. My code is running fine but it gives an Exception as follows:

   Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOfRange(Arrays.java:3209)
at java.lang.String.<init>(String.java:215)
at java.nio.HeapCharBuffer.toString(HeapCharBuffer.java:542)
at java.nio.CharBuffer.toString(CharBuffer.java:1157)
at java.util.regex.Matcher.toMatchResult(Matcher.java:232)
at java.util.Scanner.match(Scanner.java:1270)
at java.util.Scanner.nextLine(Scanner.java:1517)
at lexiconbuild.model.Lexicon.<init>(Lexicon.java:29)
at lexiconbuild.model.LexiconBuild.main(LexiconBuild.java:17)
Java Result: 1

I was wondering if someone could help me with increasing the java heap space in netbeans.

Answer 1

You can set it in NetBeans in the project properties -> Run -> VM options

1. Right click on your project " Properties "
2. Select " Run " category.
3. Enter your arguments( -Xmx512m ) in the " VM Options " text box.

Example: Putting -Xmx512m in the "VM Options" text box gives 512Mb maximum heap size to your Java program.

Answer 2

if you want to change it for netbeans it self you can change it from this file:

netbeans.conf 

you will find it in netbeans folder under /etc

and there is two parameters for the heap

Xms - the initial size of the heap.

Xmx - max java heap size

it using the default, you just have to add it there and try to add them both.

and also don't forget to add those to netbeans_default_options when you change the XMX

-J-XX:+UseConcMarkSweepGC -J-XX:+CMSClassUnloadingEnabled -J-XX:+CMSPermGenSweepingEnabled

so netbeans_default_options will be something like that:

netbeans_default_options="-J-client -J-Xss2m -J-Xms512m -J-Xmx1024m -J-XX:PermSize=256m -J-Dapple.laf.useScreenMenuBar=true -J-Dapple.awt.graphics.UseQuartz=true -J-Dsun.java2d.noddraw=true -J-Dsun.zip.disableMemoryMapping=true -J-XX:+UseConcMarkSweepGC -J-XX:+CMSClassUnloadingEnabled -J-XX:+CMSPermGenSweepingEnabled"

Answer 3

In the run configuration you should set Java VM option -Xmx512m or other that limits the maximum size of the Java VM to 512M. You can always experiment with other values. You are only limited with physical memory used by the OS.