By default, Swing uses a cross-platform look and feel called Metal. This default can be changed with a system property on the command line, an entry in a properties file, or programmatically (see e867 Getting and Setting a Look and Feel). 
The following example demonstrates how to set the look and feel using a system property on the command line: 

    > java -Dswing.defaultlaf=com.sun.java.swing.plaf.windows.WindowsLookAndFeel MyApp


Alternatively, the default look and feel can be set in a properties file called `swing.properties' located in the `<JAVAHOME>/lib' directory. The name of the property is swing.defaultlaf. 
    # Specify the default look and feel
    swing.defaultlaf=com.sun.java.swing.plaf.windows.WindowsLookAndFeel