DKPro TC is a UIMA-based text classification framework built on top of DKPro Core and DKPro Lab. It is intended to alleviate supervised machine learning experiments with any kind of textual data.
Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window dkpro-tc-0.7.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.