Want to know more about standard Java I/O concepts like standard input, standard output, and standard error? Read on!

For new Java programmers, the JOptionPane class is a great visual and user-friendly introduction to user input and Swing-based programming. Here's how to get started.

Need to add multiple values to a key in a Java HashMap but can't figure out how to do it? Here are three examples of how to solve the multiple values per key problem in Java.