OutOfMemoryError: Java heap space error when exporting more than 65MB file

Question

Hi all,
My requirement is to export 65Mb file in a CSV format.There is no possibility for me to increase the heap size.
But ,I get the following error which is below the code while doing an export.
Whole 65mb ,I am putting into the response stream.I am not sure whether this is allowed or not.If not,please tell me the alternatives.
ServletOutputStream out = null;
final FacesContext faces = FacesContext.getCurrentInstance();
final HttpServletResponse response = (HttpServletResponse) faces
.getExternalContext().getResponse();
response.setContentType( "application/download" );
response.setHeader( ...................);
final byte[] byteArray = eachLine.toString().getBytes();
response.setContentLength( byteArray.length );
out.write(byteArray);
java.lang.OutOfMemoryError: Java heap space
at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:95)
at org.apache.myfaces.webapp.filter.ExtensionsResponseWrapper$MyServletOutputStream.write(ExtensionsResponseWrapper.java:138)
at org.ajax4jsf.io.FastBufferOutputStream.writeTo(FastBufferOutputStream.java:151)
at org.ajax4jsf.framework.ajax.xmlfilter.FilterServletResponseWrapper.sendContent(FilterServletResponseWrapper.java:469)
at org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:193)
at org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:220)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:100)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:147)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
Edited by: Neelims on Apr 4, 2009 3:48 AM
Edited by: Neelims on Apr 4, 2009 3:51 AM

Answer 1

Hi
final byte[] byteArray = eachLine.toString().getBytes();
response.setContentLength( byteArray.length );
out.write(byteArray);
I assume eachLine is an object that holds the 100MB file contents, just release the memory held by this object before you start the writing part as shown below
final byte[] byteArray = eachLine.toString().getBytes();
eachLine=null;//removed the reference holding the memory
System.gc()//if JVM is in a good mood may be it will release some memory
response.setContentLength( byteArray.length );
out.write(byteArray);
before throwing out of memeory JVM may try to run the garbage collecter as you have initialised your object it might free up some memory