GLib
· GLib provides the core application building blocks for libraries and applications written in C. It provides the core object system used in GNOME, the main loop implementation, and a large set of utility functions for strings and common data structures.
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 glib2-ndk26-static-2.78.1-beta-1.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.