CircularImageView
· CircularImageView is a checkable Android ImageView implementation that draws circular images with support for optional placeholder text. CircularImageView supports Picasso & Glide.
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 circularimageview-1.2.2.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.