请先看以下两段代码(分别选自 Core Java 5E 和 Core Java 7E),不同之处已用蓝色表明。
      程序一:     public class Welcome     {        public static void main(String[] args)        {           String[] greeting = new String[3];           greeting[0] = "Welcome to Core Java";           greeting[1] = "by Cay Horstmann";           greeting[2] = "and Gary Cornell";                for (int i = 0; i < greeting.length; i++)              System.out.println(greeting[i]);        }     }
      程序二:     public class Welcome     {        public static void main(String[] args)        {           String[] greeting = new String[3];           greeting[0] = "Welcome to Core Java";           greeting[1] = "by Cay Horstmann";           greeting[2] = "and Gary Cornell";                for (String g : greeting)              System.out.println(g);        }     } 
    这两个程序输出的结果是相同的,均为:     Welcome to Core Java     by Cay Horstmann     and Gary Cornell
      而程序二如果使用JDK1.4或以下版本编译就会出错,使用1.5则可顺利通过。这说明了此“:”操作符是JDK1.5新加的特性之一。  
 
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