NimbusLookAndFeel cannot be resolved to a variable

Question

I am trying to learn the basic GUI using swing. When I tried to activate/set nimbus, the following error is shown "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel cannot be resolved to a variable". The error is shown in the com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel line in setLookAndFeel() method. I am using java build 1.7.0

import java.awt.FlowLayout;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.*;

public class swing1 extends JFrame {
    public swing1(){
        super("Title: Swing Project 1");
        //setLookAndFeel();
        setSize(225,80);
        setLookAndFeel();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        FlowLayout flo = new FlowLayout();
        JButton adds = new JButton ("Add");
        JButton minus = new JButton("Substract");
        JButton mult = new JButton ("Multiply");
        add(adds);
        add(minus);
        add(mult);
        setVisible(true);                   
    }

    private void setLookAndFeel() {
        // TODO Auto-generated method stub
        try {
            UIManager.setLookAndFeel(“com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel”);
        }
        catch (Exception exc) {
            //ignore
        }       
    }

    public static void main (String args   []){
        swing1 startSwing = new swing1();
    }
}

Answer 1

Literal String you define with " not with “

Also use this code to set Look and Feel.

import javax.swing.UIManager.*;

try {
    for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
        if ("Nimbus".equals(info.getName())) {
            UIManager.setLookAndFeel(info.getClassName());
            break;
        }
    }
} catch (Exception e) {
    // If Nimbus is not available, you can set the GUI to another look and feel.
}

From official Nimbus Look and Feel.

Version Note: Do not set the Nimbus look and feel explicitly by invoking the UIManager.setLookAndFeel method because not all versions or implementations of Java SE 6 support Nimbus. Additionally, the location of the Nimbus package changed between the JDK 6 Update 10 and JDK 7 releases. Iterating through all installed look and feel implementations is a more robust approach because if Nimbus is not available, the default look and feel is used. For the JDK 6 Update 10 release, the Nimbus package is located at com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel.

Answer 2

Use regular quotes

"com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"

instead of

“com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel”

Answer 3

If you read the documentation at The Java Tutorials, you'll see that between releases of Java 6 and Java 7, the location of the Nimbus Look-and-Feel package changed. The recommended way to set the look-and-feel to Nimbus is this:

import javax.swing.UIManager.*;

try {
    for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
        if ("Nimbus".equals(info.getName())) {
            UIManager.setLookAndFeel(info.getClassName());
            break;
        }
    }
} catch (Exception e) {
    // If Nimbus is not available, you can set the GUI to another look and feel.
}

Answer 4

This is the way I do to set Nimbus

import javax.swing.UIManager.LookAndFeelInfo;
import java.awt.EventQueue;
import java.awt.BorderLayout;
import javax.swing.*;
public class Frame1 {
    private JFrame frame;
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {

                     for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
                            if ("Nimbus".equals(info.getName())) {
                                UIManager.setLookAndFeel(info.getClassName());
                                break;
                            }
                        }
                Frame1 window = new Frame1();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }