小编Rya*_*yan的帖子

Java语言规范的4.2节规定,"原始值不与其他原始值共享状态".这到底是什么意思？

我想测试Runnable接口.创建实现接口Runnable的类的实例.然后由同一个实例创建三个线程.观察线程如何共享实例的字段变量. 两个问题:1.为什么两个结果不像"20,19,18 ...... 1,0"的顺序？2.为什么这两个结果彼此不同？(我运行代码两次.) 代码如下:

public class ThreadDemo2 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        TestThread tt = new TestThread();
        Thread t1 = new Thread(tt);
        Thread t2 = new Thread(tt);
        Thread t3 = new Thread(tt);
        t1.start();
        t2.start();
        t3.start();
    }
}
class TestThread implements Runnable {
    public int tickets = 20;
    public void run(){
        while (tickets >= 0){
            System.out.println(Thread.currentThread().getName() + ":the number of tickets is " + tickets--);
        }
    }
}

我运行代码两次.两个结果如下所示. 第一次:

Thread-1:the number of …

下面显示了几种创建字符串的方法.在注释的表达式后面添加问题.

String str = "test";
String str1 = new String(str);  //Will it invoke the Constructor of String(String)?
String str2 = new String("test");//Will it invoke the Constructor of String(String)?
String str3 = str; //Which Constructor will it invoke? Or str3 only reference to str and "test" without being constructed?
String str4 = "test";//Which Constructor will it invoke? Or str4 only reference to str and "test" without being constructed?
String strnew = new String("testnew");//Will this expression create "testnew" in String Constant Pool …