区别

run()

只是一个普通的方法调用，不会开启新的线程。

start()

会开启新的线程，分配新的资源。里面的变量互不影响。

实例

package multithreading; public class MyThread extends Thread { String flag; public MyThread(String flag) { this.flag = flag; } @Override public void run() { String tname = Thread.currentThread().getName(); System.out.println(tname + "线程的run方法被调用……"); for (int i = 0; i < 5; i++) { try { Thread.sleep(200); System.out.println(tname + "...." + flag); } catch (InterruptedException e) { e.printStackTrace(); } } } public static void main(String[] args) { MyThread t1 = new MyThread("a"); MyThread t2 = new MyThread("b"); MyThread t3 = new MyThread("c"); t1.run(); t2.run(); t3.run(); System.out.println("-------------分割线-----------"); t1.start(); t2.start(); t3.start(); } }

运行结果

main线程的run方法被调用…… main....a main....a main....a main....a main....a main线程的run方法被调用…… main....b main....b main....b main....b main....b main线程的run方法被调用…… main....c main....c main....c main....c main....c -------------分割线----------- Thread-0线程的run方法被调用…… Thread-2线程的run方法被调用…… Thread-1线程的run方法被调用…… Thread-0....a Thread-2....c Thread-1....b Thread-2....c Thread-0....a Thread-1....b Thread-0....a Thread-2....c Thread-1....b Thread-2....c Thread-0....a Thread-1....b Thread-2....c Thread-0....a Thread-1....b