Suppose you want to pass a Boolean system property, -DDEBUG=true or -DDEBUG=false, from the command line. Normally, you’d probably use the following in source code to retrieve it:

 boolean b = Boolean.valueOf(System.getProperty("DEBUG")).booleanValue();if(b) {    //do something;}or just treat it as a string system property:if(System.getProperty("DEBUG").equalsIgnoreCase("true")) {    //do something;}

The following code offers an easier way to do the same thing:

 public class GetBoolean {    public static void main(String args[]) throws Exception {        if(Boolean.getBoolean("DEBUG")) {            System.out.println("Debug is on");        } else {            System.out.println("Debug is off");        }    }}

The GetBoolean class is tested under JDK1.3.1 with the following output:

 D:foo>java -DDEBUG=true GetBooleanDebug is onD:foo>java -DDEBUG=false GetBooleanDebug is offD:foo>java -DDEBUG=TRue GetBooleanDebug is onD:foo>java -DDEBUG=Yes GetBooleanDebug is offD:foo>java GetBooleanDebug is off