programming-examples/java/Servlets_Session_Swing_Util/A scoping example.java

A scoping example

  import java.awt.Container;
 import javax.swing.*;
 
 public class Scoping extends JApplet 
 {
	 JTextArea outputArea;
	 int x = 1; // instance variable

	 public void init()
	 {
		 outputArea = new JTextArea();
		 Container c = getContentPane();
		 c.add( outputArea );
	 }

	 public void start()
	 {
		 int x = 5; // variable local to method start

		 outputArea.append( "local x in start is " + x );

		 methodA(); // methodA has automatic local x
		 methodB(); // methodB uses instance variable x
		 methodA(); // methodA reinitializes automatic local x
		 methodB(); // instance variable x retains its value

		 outputArea.append( "\n\nlocal x in start is " + x );
	 }

	 public void methodA()
	 {
		 int x = 25; // initialized each time a is called

		 outputArea.append( "\n\nlocal x in methodA is " + x + " after entering methodA" );
		 ++x;
		 outputArea.append( "\nlocal x in methodA is " + x + " before exiting methodA" );
	 }

	 public void methodB()
	 {
		 outputArea.append( "\n\ninstance variable x is " + x + " on entering methodB" );
		 x *= 10;
		 outputArea.append( "\ninstance variable x is " + x + " on exiting methodB" );
	 }
 }