Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.

Get a deep dive into using method references in your Java programs, including stream operations, event listeners, and constructors and factories.

The Java API will become your very close friend during this class, and you will become very familiar with it.

The correct way to convert a String to long in Java is with the parseLong method of the wrapper class. The constructor conversion approach is deprecated! Use parseLong instead.

Dagger uses fully-qualified class names embedded in strings with other characters. Proguard -adaptclassstrings option only replaces fully-qualified class names in strings all by themselves (without ...

The Java "Random" class lets you generate a random number for your Java apps. You use this number generator to randomize images shown in your apps.

How to Assign Random Numbers to an Array in Java. Java has a "Random" class that lets you generate a random number you use to implement calculations in your Java source code.

The Java API will become your very close friend during this class, and you will become very familiar with it.