Thread class how start method calls the run method of sub class

Question

请帮助我了解如何通过调用线程类的start方法来调用run方法。

Answer 1

The start() method starts a new thread of execution, and arranges things so that the new thread of execution invokes the run() method. The exact mechanics are OS-specific.

Answer 2

I would suggest to look at the source code of java.lang.Thread.start() method. Its a synchronized method which in turn calls private native method and then the OS specific threading mechanism takes over ( which eventually calls the run() method of the current object )

Answer 3

From docs

public void start()

Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.

The result is that two threads are running concurrently: the current thread (which returns from the call to the start method) and the other thread (which executes its run method).

Answer 4

Thread start() call run() is an internal process, while threading is platform dependent.

Following is what Java developers say

java.​lang.​Thread
public synchronized void start()
Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.
The result is that two threads are running concurrently: the current thread (which returns from the call to the start method) and the other thread (which executes its run method).
It is never legal to start a thread more than once. In particular, a thread may not be restarted once it has completed execution.
Throws:
IllegalThreadStateException - if the thread was already started. 
See Also:
Thread.run(), Thread.stop()

You sure don't have to worry about this. If you are seeking for an thread example, here is one

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class ThreadEx extends JFrame
{
    private JLabel numTxt;
    private JButton click;
    private Thread t = new Thread(new Thread1());

    public ThreadEx()
    {
        numTxt = new JLabel();
        click = new JButton("Start");
        click.addActionListener(new ButtonAction());

        JPanel centerPanel = new JPanel();
        centerPanel.setLayout(new FlowLayout());
        centerPanel.add(numTxt);
        centerPanel.add(click);

        this.add(centerPanel,"Center");

        this.pack();
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private class Thread1 implements Runnable
    {

        @Override
        public void run() 
        {
            try
            {
                for(int i=0;i<100;i++)
                {
                    numTxt.setText(String.valueOf(i));
                    Thread.sleep(1000);
                }
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }

    }

    private class ButtonAction implements ActionListener
    {

        @Override
        public void actionPerformed(ActionEvent e)
        {
            t.start();
        }

    }

    public static void main(String[]args)
    {
        new ThreadEx();
    }
}