The simplest way to launch a Java program is to run it using the Java Application launch configuration. This launch configuration uses information derived from the workbench preferences and your program's Java project to launch the program.
You can also launch a Java program by selecting a project instead of the compilation unit or class file. You will be prompted to select a class from those classes that define a main method. (If only one class with a main method is found in the project, that class is launched as if you selected it.)
You can launch a program from an open editor by using Run > Run As > Java Application in the editor's popup menu.
Java views
Java editor
Debugger
Connecting to a remote VM with the Java Remote Application launcher
Relaunching a program
Running and debugging
Setting execution arguments
Stepping through the execution of a program