Launch an HTML file in the default browser : Program « SWT « Java Tutorial

import org.eclipse.swt.program.Program;

public class MainClass {
  public static void main(String[] args) {

17.123.1.Run the appropriate program for that data file and load the data file into the program.
17.123.2.Launch an HTML file in the default browser
17.123.3.Look up which program to use
17.123.4.Get all extensions on your system
17.123.5.Show the extensions on the system and their associated programs
17.123.6.Execute program