The com.Ostermiller.util package is open source you can download the source code, make modifications, and distribute your changes in accordance with the license. To get started, choose the "latest source code" from the downloads. Extract the package and build it with Maven.
There are several build dependencies such as JFlex, however, Maven will take care of them for you and download all needed libraries and software. Upon a successful build, you should find several .jar, .zip, .gz, and .bz2 files built in the target directory.