1）继承Thread类的子类：

class FirstThread extends Thread{
    @Override
    public void run() {
        System.err.println("first thread.");
    }
}
new FirstThread().start();
2）实现Runnable接口

class SecondThread implements Runnable{
    @Override
    public void run() {
        System.err.println("second thread.");
    }
}
new Thread(new SecondThread()).start();
3）实现Callable接口来创建Thread线程

class ThreeCallable implements Callable<Integer>{
    @Override
    public Integer call() throws Exception {
        int i = 0;
        for(;i<100;i++)
        {
            System.out.println(Thread.currentThread().getName()+" "+i);
        }
        return i;
    }
}
ThreeCallable threeCallable = new ThreeCallable();
FutureTask<Integer> ft = new FutureTask<Integer>(threeCallable);
new Thread(ft).start();
System.err.println("ft:"+ft.get());
4）利用线程池创建多线程的方式

Executors.newFixedThreadPool(3).execute(new Runnable() {
    @Override
    public void run() {
        System.out.println("newFixedThreadPool_" + Thread.currentThread().getName());
    }
});
Executors.newCachedThreadPool().execute(new Runnable() {
    @Override
    public void run() {
        System.out.println("newCachedThreadPool_" + Thread.currentThread().getName());
    }
});
Executors.newScheduledThreadPool(3).execute(new Runnable() {
    @Override
    public void run() {
        System.out.println("newScheduledThreadPool_" + Thread.currentThread().getName());
    }
});

1）继承Thread类的子类：

class FirstThread extends Thread{
    @Override
    public void run() {
        System.err.println("first thread.");
    }
}
new FirstThread().start();
2）实现Runnable接口

class SecondThread implements Runnable{
    @Override
    public void run() {
        System.err.println("second thread.");
    }
}
new Thread(new SecondThread()).start();
3）实现Callable接口来创建Thread线程

class ThreeCallable implements Callable<Integer>{
    @Override
    public Integer call() throws Exception {
        int i = 0;
        for(;i<100;i++)
        {
            System.out.println(Thread.currentThread().getName()+" "+i);
        }
        return i;
    }
}
ThreeCallable threeCallable = new ThreeCallable();
FutureTask<Integer> ft = new FutureTask<Integer>(threeCallable);
new Thread(ft).start();
System.err.println("ft:"+ft.get());
4）利用线程池创建多线程的方式

Executors.newFixedThreadPool(3).execute(new Runnable() {
    @Override
    public void run() {
        System.out.println("newFixedThreadPool_" + Thread.currentThread().getName());
    }
});
Executors.newCachedThreadPool().execute(new Runnable() {
    @Override
    public void run() {
        System.out.println("newCachedThreadPool_" + Thread.currentThread().getName());
    }
});
Executors.newScheduledThreadPool(3).execute(new Runnable() {
    @Override
    public void run() {
        System.out.println("newScheduledThreadPool_" + Thread.currentThread().getName());
    }
});