영혼과영혼의양식

이전 예제에서 main method가 Thread가 종료되기 전에 종료됨.
Thread가 종료된 후에 main method가 종료시켜야 하는 경우 사용하는 방법

ThreadExam01.java

public class ThreadExam01 extends Thread {
	int seq;
	
	public ThreadExam01(int seq){
		this.seq = seq;
	}
	
	@Override
	public void run() {
		System.out.println(this.seq + " thread START");
		
		try{
			Thread.sleep(1000);
		}catch(Exception ex){
			ex.printStackTrace();
		}
		
		System.out.println(this.seq + " thread END");
	}
}

public class ThreadMain01 {

	public static void main(String[] args) {
		List threadList = new ArrayList<>();
		
		try{
			for(int i=0; i<5; i++){
				Thread thread = new ThreadExam01(i);
				thread.start();
				
				threadList.add(thread);
			}
			
			for(int i=0; i<'threadList.size()'; i++){
				Thread th = threadList.get(i);
				th.join();
			}
		}catch(Exception ex){
			ex.printStackTrace();
		}			
		
		System.out.println("ThreadMain01 END...");
	}
}

1 thread START
4 thread START
0 thread START
3 thread START
2 thread START
3 thread END
4 thread END
2 thread END
0 thread END
1 thread END
ThreadMain01 END...

public class ThreadExam02 implements Runnable {
	int seq;
	
	public ThreadExam02(int seq) {
		this.seq = seq;
	}
	
	@Override
	public void run() {
		System.out.println(this.seq + " thread START");
		
		try{
			Thread.sleep(2000);
		}catch(Exception ex){
			ex.printStackTrace();
		}
		
		System.out.println(this.seq + " thread END");
	}
}

public class ThreadMain02 {

	public static void main(String[] args) {
		List threadList = new ArrayList<>();
		
		try{
			for(int i=0; i<5; i++){
				Thread thread = new Thread(new ThreadExam02(i));
				thread.start();
				
				threadList.add(thread);
			}
			
			for(int i=0; i<'threadList.size()'; i++){
				Thread th = threadList.get(i);
				th.join();
			}
			
			System.out.println("ThreadMain02 END");
		}catch(Exception ex){
			ex.printStackTrace();
		}
	}
}

1 thread START
0 thread START
3 thread START
2 thread START
4 thread START
3 thread END
0 thread END
4 thread END
2 thread END
1 thread END
ThreadMain02 END

Main class
public class ThreadMain03 {
	
	public static void main(String[] args) {
		System.out.println("ThreadMain03 START");

		try{
			for(int i=0; i<5; i++){
				Thread exam03 = new ThreadExam03((i+1) + "번째");
				exam03.start();
				exam03.join();	//쓰레드가 종료될 때까지 대기
			}
		}catch(Exception ex){
			ex.printStackTrace();
		}
		
		System.out.println("ThreadMain03 END");
	}
}


//ThreadExam03 Thread class
class ThreadExam03 extends Thread {
	String threadName;
	
	public ThreadExam03(String name) {
		this.threadName = name;
	}
	
	@Override
	public void run() {
		System.out.println(this.threadName + " START");
		
		try{
			Thread.sleep(2000);
		}catch(Exception ex){
			ex.printStackTrace();
		}
		
		System.out.println(this.threadName + " END");
	}
}

ThreadMain03 START
1번째 START
1번째 END
2번째 START
2번째 END
3번째 START
3번째 END
4번째 START
4번째 END
5번째 START
5번째 END
ThreadMain03 END