android-pdf-viewer
· PdfViewer - Library for displaying PDF documents on Android, with animations, gestures, zoom and double tap support. This is improved version of AndroidPdfViewer library for easy integration with VGS products for Android.
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 android-pdf-viewer-1.0.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.