Here you can find the source of isNimbusGTKTheme()
public static boolean isNimbusGTKTheme()
//package com.java2s; //License from project: Open Source License import java.awt.Toolkit; import javax.swing.UIManager; public class Main { /**//from w w w . ja v a 2 s. c om * Determines if current L&F is GTK using Nimbus theme */ public static boolean isNimbusGTKTheme() { // is current L&F GTK using Nimbus theme? return isGTKLookAndFeel() && "nimbus".equals(Toolkit.getDefaultToolkit().getDesktopProperty("gnome.Net/ThemeName")); //NOI18N } /** * Determines if current L&F is GTKLookAndFeel */ public static boolean isGTKLookAndFeel() { // is current L&F some kind of GTKLookAndFeel? return UIManager.getLookAndFeel().getID().equals("GTK"); //NOI18N } }