java - Class is not abstract and does not override abstract method actionPerformed(ActionEvent) in ActionListener -


please help. i'm not new coding, new java. don't know i'm doing wrong. i'm using book learn java, , following code i'm working on @ moment. went books website , downloaded source program , gave me same error message. please help. know has been asked about, i'm stuck , use help. 

import java.awt.event.*; import javax.swing.*; import java.awt.*;  public class titlebar extends jframe implements actionlistener {     jbutton b1;     jbutton b2;      public titlebar() {         super("title bar");         setdefaultcloseoperation(jframe.exit_on_close);         setlookandfeel();         b1 = new jbutton("rosencrantz");         b2 = new jbutton("guildenstern");         b1.addactionlistener(this);         b2.addactionlistener(this);         flowlayout flow = new flowlayout();         setlayout(flow);         add(b1);         add(b2);         pack();         setvisible(true);     }      public void actionperformed(actionevent evt) {         object source = evt.getsource();         if (source == b1) {             settitle("rosencrantz");         } else if (source == b2) {             settitle("guildenstern");         }         repaint();     }      private void setlookandfeel() {         try {             uimanager.setlookandfeel(                 "com.sun.java.swing.plaf.nimbus.nimbuslookandfeel"             );             swingutilities.updatecomponenttreeui(this);         } catch (exception exc) {             system.err.println("couldn't use system "                 + "look , feel: " + exc);         }     }      public static void main(string[] arguments) {         titlebar frame = new titlebar();     } }

your class works me. try imports

import java.awt.flowlayout; import java.awt.event.actionevent; import java.awt.event.actionlistener;  import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.swingutilities; import javax.swing.uimanager;

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