Java developers

Can someone explain what it is? One of my programs seems to have a memory leak and I looked at it in jconsole. The heap size keeps going up and down depending on what the program is doing, and the garbage collector activity; the heap broken into different parts, one of which is "PS Old Gen". Its size is creeping up very slowly.

Could anybody figure out what's going on? I'm instantiating a parser, and this is what I get when I try to read:

java.lang.NullPointerException

        at weblogic.xml.jaxp.SAXFactoryProperties.get(SAXFactoryProperties.java:

57)

        at weblogic.xml.jaxp.RegistryParser.getParser(RegistryParser.java:278)

        at weblogic.xml.jaxp.RegistryParser.parse(RegistryParser.java:139)

        at com.myjavatools.xml.XmlReader.read(XmlReader.java:323)

Myjavatools is my opensource library; line 323 looks like this:

       SAX_parser.parse(src);

where InputSource src is just an InputSource instantiated like this:

  public XmlReader(Reader in)
    throws java.io.IOException, InstantiationException {
    ...

    src = new InputSource(in);
 

Any help, any hints?