Is it correct to start the thread inside its constructor, or is this a bad practice?

[ashen niche]

Like this:

package com.pong.gamedisplay;

public class TimerThread extends Thread implements Runnable {

    private int secondsLeft;
    
    public TimerThread(int seconds) {
        secondsLeft = seconds;
        this.start();
    }
    
    @Override
    public void run() {
        try {
            Thread.sleep(1000);
        }
        catch (InterruptedException e) {}
        
        secondsLeft--;
        if (secondsLeft == 0) {
            this.interrupt();
        }
    }
    
    public int getSecondsLeft() {
        return secondsLeft;
    }
    
}

also is it redundant to implement Runnable in the TimerThread class if the parent class Thread already implements it? I am not getting any error no matter if I implement it to the TimerThreador not

[woeful ridge]

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[clever topaz]

Yes, it is bad practice. And yes, you don't need to declare your class to implement Runnable when its parent class already does.

Your constructor should only do basic assignment stuff, never any complex logic that could have side-effects

because when someone does new TimerThread(), not knowing what your class does exactly, they're not gonna expect it to spawn a thread before you even call a method on the object.

[ashen niche]

alright, thanks for the help

[woeful ridge]

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