We are developing an application on struts framework for FTP upload and download using apache commons-net-1.4.1.jar. We are using java 1.4 and Webshpere server 5.1. It is working successfully for files < 20 MB. But if the file size exceeds 20MB it is giving no problem in uploading, but while downloading the file we are getting OutofMemory exception.

JVMDG217: Dump Handler is Processing a Signal - Please Wait.
JVMDG315: JVM Requesting Heap dump file
...JVMDG318: Heap dump file written to D:\Program Files\IBM\WebSphere Studio\Application Developer\v5.1.2\heapdump.20081113.150210.2496.txt
JVMDG303: JVM Requesting Java core file
JVMDG304: Java core file written to D:\Program Files\IBM\WebSphere Studio\Application Developer\v5.1.2\javacore.20081113.150231.2496.txt
JVMDG215: Dump Handler has Processed Outofmemory Signal -1.
[11/13/08 15:32:34:959 IST] 491dbdf1 WebGroup E SRVE0026E: [Servlet Error]-[]: java.lang.OutOfMemoryError:
at java.lang.StringCoding.decode(StringCoding.java:38 6)
at java.lang.StringCoding.decode(StringCoding.java:45 5)
at java.lang.String.<init>(String.java:728)
at java.io.ByteArrayOutputStream.toString(ByteArrayOu tputStream.java(Inlined Compiled Code))

Is this problem due to server settings? If so, I will be thankful if anyone can let me know where we can set the memory size in Websphere console? If we use Websphere Application Server 6.1 can this problem be avoided?