Is there a general JAVA library for converting text file from a format to another?

[vicseo]

I'm working on a Java software that takes as input text files that are in a particular file format that I will call X.Now, my problem is as follows. The users of my software want to convert files that are not in format X to the format X used by my software.I would like to give to the user a user-friendly tool for converting any text file format to X.To make the software user-friendly, I think that a solution would be to let the user specify his input file format in XML or something else and then let my software convert automatically his file to X.Are there some open-source tools or library in Java (preferably GPL) for converting text file that use a file format specification like XML or something similar? I could write this by myself. But I don't want to reinvent the wheel. I know that a possibility would be to use XSLT transformation to transform text files. But I would like to know if there are other alternatives.