Do not use the removed com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel or apple.laf.AquaLookAndFeel Swing LookAndFeel

This rule flags the following strings:

• "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"
• "apple.laf.AquaLookAndFeel"

Those strings are no longer supported as parameters to the javax.swing.UIManager.setLookAndFeel method. Instead:

• Replace "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel" with "javax.swing.plaf.nimbus.NimbusLookAndFeel"
• Replace "apple.laf.AquaLookAndFeel" with a call to UIManager.getSystemLookAndFeelClassName()

For more information on Java SE 11 changes, see Java 10 Removed Features and Options.