For a quick example of setting up Eclipse and creating a Java program, check out my last tutorial. That tutorial explains the benefits of using Java as your primary programming language, and writing your first Java program. There are literally thousands of programming languages out there, but Java is a strong versatile language for doing most types of computer programming in.
As mentioned in my last Java tutorial, Eclipse is an IDE used for creating Java programs. When you open Eclipse, you choose a workspace to develop in. Workspaces are just folders on your computer. Usually, a workspace contains projects that represent a program related library.
You can create as many workspaces as you want and only place related projects in workspaces together. For instance, you might have one workspace for school assignments, and another workspace for work tasks.