Main.java

import java.util.Scanner;
import java.util.concurrent.Semaphore;

public class Main {

	static class W1 extends Thread{
		public static int a;
		private Semaphore s;
		private Semaphore s0;

		public W1(Semaphore s0, Semaphore s){
			this.s0 = s0;
			this.s = s;
		}

		@Override
		public void run() {
			Scanner in = new Scanner(System.in);
			System.out.print("Podaj A: ");
			a = in.nextInt();
			this.s.release();
			this.s0.release();
		}
	}

	static class W2 extends Thread{
		public static int b;
		private Semaphore s;
		private Semaphore s0;

		public W2(Semaphore s0, Semaphore s){
			this.s0 = s0;
			this.s = s;
		}

		@Override
		public void run() {
			try {
				this.s0.acquire();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			Scanner in = new Scanner(System.in);
			System.out.print("Podaj B: ");
			b = in.nextInt();
			this.s.release();
		}
	}

	static class W3 extends Thread{
		Semaphore s1, s2;

		public W3(Semaphore s1, Semaphore s2){
			this.s1 = s1;
			this.s2 = s2;
		}

		@Override
		public void run() {
			try {
				s1.acquire();
				s2.acquire();
				System.out.println("Suma to: " + (W1.a + W2.b));
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		Semaphore s0 = new Semaphore(0);
		Semaphore s1 = new Semaphore(0);
		Semaphore s2 = new Semaphore(0);

		new W1(s0,s1).start();
		new W2(s0,s2).start();
		new W3(s1, s2).start();
	}
}

dzięki działa