How to best output large single line XML file (with Java/Eclipse)?

Question

We have a process that outputs the contents of a large XML file to System.out.

When this output is pretty printed (ie: multiple lines) everything works. But when it's on one line Eclipse crashes with an OutOfMemory error. Any ideas how to prevent this?

Answer 1

How do you print it on one line?

• using several System.out.print(String s)
• using System.out.println(String verybigstring)

in the second case, you need a lot more memory...

If you want more memory for eclipse, could try to increase eclipses memory by changing the -Xmx value in eclipse.ini

Answer 2

I'm going to assume that you're building an org.w3c.Document, and writing it using a serializer. If you're hand-building an XML string, you're all but guaranteed to be producing something that's almost-but-not-quite XML, and I strongly suggest fixing that first.

That said, if you're writing to a stream from the serializer (and System.out is a stream), then you should be writing directly to the stream rather than writing to a string and printing that (which you'd do with a StringWriter). The reason for this is that the XML serializer will properly handle character encodings, while serializer to String to stream may not.

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If you're not currently building a DOM, and are concerned about the memory requirements of doing so, then I suggest looking at the Practical XML library (which I maintain), in particular the builder package. It uses lightweight nodes, that are then output via a serializer using a SAX transform.

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Edit in response to comment:

OK, you've got the serializer covered with XStream. I'm next going to assume that you are calling XStream.toXML(Object) to produce the string, and recommend that you call the variant toXML(Object, OutputStream), and pass it the actual output. The reason for this is that XML is very sensitive to character encoding, which is something that often breaks when converting strings to streams.

This may, of course, cause issues with building your POST request, particularly if you're using a library that doesn't provide you an OutputStream.

Answer 3

Sounds like it is the Console panel blowing up. Consider limiting its buffer size.

EDIT: It's in Preferences. Search for Console.