什么似乎不符合JLS所说的那样,当使用String连接与一个转换的常量String类型创建一个新的String时,它应该被视为一个JLS的常量String,显然JVM正在创建一个新的字符串对象,而不是隐含地实现它.我感谢关于这个特定行为的任何解释,以及这是否是平台特定的行为.我在Mac OSX Snow Leopard上运行.

public class Test
{
    public static void main(String args[])
    {
        /*
            Create a String object on the String constant pool
            using a String literal
        */
        String hello = "hello";
        final String lo = "lo"; // this will be created in the String pool as well
        /*
            Compare the hello variable to a String constant expression,that should cause the JVM to implicitly call String.intern()
        */
        System.out.println(hello == ("hel" + lo));// This should print true
        /*
            Here we need to create a String by casting an Object back
            into a String,this will be used later to create a constant
            expression to be compared with the hello variable
        */
        Object object = "lo";
        final String stringObject = (String) object;// as per the JLS,casted String types can be used to form constant expressions
        /*
            Compare with the hello variable
        */
        System.out.println(hello == "hel" + stringObject);// This should print true,but it doesn't :(

    }
}