Errors (exceptions) are handled using try-catch. Most of the examples relate to input/output since most I/O operations throw exceptions and require an understanding of try-catch. Thus these two topics are tightly integrated. The minor topics of constants and enums are not connected to errors or file I/O in any way.
See "Rotating an object" for an example of a timer
Example of animation WITHOUT timer: GraphicsMain.java and Shape.java
Quick summary on how to load and draw BufferedImages (from grade 11).
This is a brief summary of the main topics. There are more details in each linkColourRainbow.java is here. It's handy if you want rainbow colours.