File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Java in General and the fly likes how to increase jvm heap size in jdk1.5.0 Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Java in General
Bookmark "how to increase jvm heap size in jdk1.5.0" Watch "how to increase jvm heap size in jdk1.5.0" New topic

how to increase jvm heap size in jdk1.5.0

durgaprasad ganji

Joined: Mar 01, 2007
Posts: 7
Hi all,

I am getting java.lang.OutOfMemoryError: Java heap space Exception ,

when running below java class in eclipse editor by configuring JVM of JDK1.5.0 within eclipse (or at command prompt) on windows platform

by using below class I am merging two Index Directories(one is 1.87 GB of size and other one is 522 MB of size) into new one using Lucene API
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.IndexWriter;
public class MergeIndex {

private MergeIndex (){

public static void main(String arg[]) throws InvalidDocDBXMLFormatException {


}catch(Exception e){


public static void mergeIndexes() {

try {
System.out.println("before add indexwriter");
IndexWriter writerDisk = new IndexWriter(FSDirectory.getDirectory(new File("D:\\DocServerData\\MergedIndexes\\DocDB1_Category1_Index"), true),new StandardAnalyzer(),true);
long l1 = System.currentTimeMillis();
System.out.println("before addIndexes method>>>>"+l1);
writerDisk.addIndexes(new Directory[]{FSDirectory.getDirectory(new File("E:\\1lac-7mar\\DocDB1_Category1_Index"), false),FSDirectory.getDirectory(new File("E:\\2lacs-19feb\\DocDB1_Category1_Index"), false)}) ;
long l2 = System.currentTimeMillis();
System.out.println("before Optimize method>>>"+ (l2-l1));
System.out.println("after Optimize method"+System.currentTimeMillis());
System.out.println("after add indexwriter");
}catch(Exception e){
System.out.println("Exception Occured>>>>>>" +e);


below is snapshot of my java class

Call tree (all threads together)
Name Time (ms)
All Threads
831,735 100 %
MergeIndex .main(String[])
831,563 100 %
171 0 %

Generated by YourKit Java Profiler 6.0.12 Mar 9, 2007 10:34:49 AM

It would be appreacited if any body tell me how to increase JAva heap size
in jvm on windows paltform
Wiyanto Ngasinur
Ranch Hand

Joined: Dec 11, 2006
Posts: 34
run your java class with command line :
java -Xmx1G [class]

this code set maximum heap 1 Giga
Deepak Bala

Joined: Feb 24, 2006
Posts: 6662

Again. Not SCJP

SCJP 6 articles - SCJP 5/6 mock exams - More SCJP Mocks
Jesper de Jong
Java Cowboy
Saloon Keeper

Joined: Aug 16, 2005
Posts: 15092

You already asked the same question, have a look at the answers there.

Java Beginners FAQ - JavaRanch SCJP FAQ - The Java Tutorial - Java SE 8 API documentation
I agree. Here's the link:
subject: how to increase jvm heap size in jdk1.5.0
It's not a secret anymore!