1    package bookExamples.ch06RefDataTypes; 
2     
3    /** 
4     * DocJava, Inc. 
5     * http://www.docjava.com 
6     * Programmer: dlyon 
7     * Date: Sep 14, 2004 
8     * Time: 3:17:57 PM 
9     */ 
10   public final class GuardedClass { 
11       public static final double PI = Math.PI; 
12       private GuardedClass(){} 
13    
14       // guard against others from making an instance. 
15       public static GuardedClass getInstance(){ 
16           return new GuardedClass(); 
17       } 
18    
19       GuardedClass gc = GuardedClass.getInstance(); 
20   } 
21