While social media websites such Facebook and LinkedIn made it incredibly easy for a user to upload image files ... deployed to any Java application server that supports the Servlet 3.1 specification ...

Such a class is known as a utility class. An example of a utility class is the Java standard class library’s Math class. Advanced techniques: Fields and methods in Java Learn seven advanced ...

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. You load the images into an array, randomly ...

It’s a good idea to use an abstract class when you need to implement mutable state. As an example, the Java Collections Framework includes the AbstractList class, which uses the state of variables.