Memory leak with JAXB

I am getting Out of Memory error:

Memory Exception in thread "main" java.l开发者_开发问答ang.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.

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.}