Thread

Thread

A thread is like a lightweight, independent path of execution inside your program

• Thread is like the smallest unit of a process
• Every Java program has at least one thread, called the main thread.

You can create additional threads to do tasks in the background while the main thread continues.

• core → thread
• 코어수 스레드 수
• context switching
  • 작업환경을 돌아다님
• types
  • 물리 스레드
    • physical available threads in hardware
  • 논리 스레스
    • 해야할 일
    • 갯수에 제한이 없음
  • virtual thread (newer java)
    • no need to use thread pool
• thread pool
  • making and saving threads to be used later
• main function
  • main thread keeps running
  • 프로그램의 가장 큰 틀을 관리함
• multi thread
  • ㅈ바는 multi thread 환경을 지원함 (node doesnt)
  • 하나의 프로세스는 여러 thread를 가질 수 있음
    • 하나의 thread를 가지고 있는데, 여러 threadㄷ가 파생된거임!
• 쓰는 방법
  • 해야할 일을 지정하는 거임
  • 방법들
    • runnable interface (함수형)
    • thread클래스를 상속받은 하위 클래스에서 run
  • thread를 생성하는 resource가 들어감
    • 생성되고 들어가는 cost가 있음
• you can get name of the thread lmao
  • thread.getName()
  • also can give name to thread .setName("thread1"), but not used as much
• Thread.sleep
  • stopping the thread
• Thread는 나중에 무조건 이해해야함

extend Thread

class Task extends Thread {
    public void run() {
        for (int i = 0; i < 3; i++) {
            System.out.println("Running in: " + Thread.currentThread().getName());
        }
    }
}
 
public class Main {
    public static void main(String[] args) {
        Task t1 = new Task();
        Task t2 = new Task();
 
        t1.start();
        t2.start();
 
        System.out.println("Main thread: " + Thread.currentThread().getName());
    }
}

• You can extend your class with {java}Thread
  • You can’t extend other class
• you have to use the start method
  • creates a new thread for you, and calls the run method of the thread automatically
• If you want to pause ur thread (milliseconds)
  • checked exception
  • {java}Thread.sleep(10)

implements Runnable

• There is no start method (only run)