Memory leak with JAXB

Question

Hi, I am getting Out of Memory error:

Memory Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at org.apache.xerces.dom.CoreDocumentImpl.createElement(CoreDocumentImpl.java:564)

I have a standalone Java program which fetches data from DB and create an XML file using DOM. I get the above error if the data fetched is huge, in my case it is > 1,000,000 records.

I have defined 2GB as heap size while calling the Java class from unix.

I tried it with JAXB, but still do not any significant improvement.

Any suggestions how to improve the code.

Answer 1

You should probably avoid loading the entire file into memory at once. To do this, switch from using DOM to another technology such as SAX or StAX. It is a streaming APIs and thus are more suited for handling huge amounts of XML data.

_{Edit: SAX doesn't support writing, therefore it's not applicable here.}