What should I put in my Main Method to make my program runnable?

Question

My program needs 2 classes which generates Threads with random numbers in decided intervals.

HeltalsGenerator defines a Thread that creates 5 randomized numbers within a decided interval, the interval gets decided when an object of the type HeltalsGenerator gets created.
SlumpTal1 creates and starts 2 Threads of the type HeltalsGenerator.
SlumpTal2 creates and starts an array of 4 Threads of the type HeltalsGenerator.

package thread;

class HeltalsGenerator extends Thread {

private int x;
private int y;

public HeltalsGenerator(int x, int y) {

    this.x = x;
    this.y = y;
}

@Override
public void run() {
    for (int i = 0; i < 5; i++) {
        int m = (int) (Math.random() * (x + 1) - y);
        System.out.println(m);
    }
    }
}

class SlumpTal1 {

Thread s1 = new Thread(new HeltalsGenerator(0, 9));
Thread s2 = new Thread(new HeltalsGenerator(-9, -1));

}

class SlumpTal2 {

Thread t1 = new Thread(new HeltalsGenerator(1, 4));
Thread t2 = new Thread(new HeltalsGenerator(5, 8));
Thread t3 = new Thread(new HeltalsGenerator(9, 12));
Thread t4 = new Thread(new HeltalsGenerator(13, 16));

Thread[] s = {t1, t2, t3, t4};
}

class Main {

public static void main(String[] args) {
    SlumpTal1 T1 = new SlumpTal1();
    T1.start();
    SlumpTal2 T2 = new SlumpTal2();
    T2.start();
    }
}

Both T1.start(); and T2.start(); creates the error "Cannot find symbol: method start() and variable T1 of SlumpTal1"

`main()` can be put in either the same class (not suggested) or a different class which actually creates and starts your threads — TheLostMind, Nov 18 '15 at 10:52

score 1 · Accepted Answer · edited May 23 '17 at 11:44

1

Make a new class and execute it.

Steps:

Create a new file Main.java (preferrable in same package/folder than the others)
Put this code on the file

public class Main {

    public static void main(String[] args) {
        // do your stuff, ask the user or what you want here, for example:
        SlumpTal1 tail1 = new SlumpTal1();  // execute 2 threads
        tail1.start();
        SlumpTal2 tail2 = new SlumpTal2();  // execute 4 threads
        tail2.start();
    }
}

Execute the app
- With your IDE (it will find automatically main method)
- From command line.
```
javac Main.java  // compile
java Main.java   // execute
```

Edit the contructor of HeltalsGenerator

public HeltalsGenerator(int x, int y) {
    super(x + "-" + y);

    this.x = x;
    this.y = y;
}

NOTES:

If all classes are NOT in same package you will need do add extra imports

edited May 23 '17 at 11:44

Community

1
1

answered Nov 18 '15 at 11:01

Jordi Castilla

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Thanks for the advice but I will need a little more guidance. When I create SlumpTal1 tail1 = new SlumpTal1(); nothing happens since I don't have a run/start command. – DuWavE Nov 18 '15 at 11:05
@DuWavE please kindly check my update and don't hesitate to ask if you have more doubts – Jordi Castilla Nov 18 '15 at 11:07
@JordiCastilla Thanks I checked out your update and I appreciate the help. I'm very new to programming so excuse my noob questions, but I created two objects in my main method and I put them in an "system.out.println" and then I just get the error "thread.SlumpTal2@2a139a55" – DuWavE Nov 18 '15 at 11:24
`thread.SlumpTal2@2a139a55` is the representation of the thread object, you have a print statement inside the `run` methods, so just start your threads with `start()`, check my edit – Jordi Castilla Nov 18 '15 at 11:37
When I write `tail1.start();` I get the error that says `Cannot find symbol: method start()`, the same with `tail2.start();`. – DuWavE Nov 18 '15 at 11:42
this is because you don't execute `super` in the constructor... [please check this question](http://stackoverflow.com/questions/541487/implements-runnable-vs-extends-thread) and my edit – Jordi Castilla Nov 18 '15 at 11:48

What should I put in my Main Method to make my program runnable?

1 Answers1