JThumbor is a project mainly written in Java, it's free.
Java library for accessing secure Thumber servers
JThumbor is a Java library that enables easy usage of secure Thumbor servers. For more information on what Thumbor is and why you might want to use this library, see the Thumbor project.
The library is licensed under the Apache License, Version 2.0.
The library is typically deployed as a JAR file. The only class most users will need to concern themselves with is the ThumborServer.
You can either grab the release from GitHub's download button or compile it yourself. The only prerequisites are self-contained in the lib folder. I use Eclipse to build the release JARs; if you want an ant build file or something, you'll have to make it yourself.