what does multithreading mean code example

Example 1: multithreading

//Bless anyone who decides to follow this path

Example 2: multithreading

from multiprocessing.pool import ThreadPool

def stringFunction(value):
    my_str = 3 + value
    return my_str


def stringFunctio(value):
    my_str = 33 + value
    return my_str

pool = ThreadPool(processes=2)

thread1 = pool.apply_async(stringFunction,(8,))
thread2 = pool.apply_async(stringFunctio,(8,))

return_val = thread1.get()
return_val1 = thread2.get()

Example 3: multithreading

class RunnableDemo implements Runnable {
   private Thread t;
   private String threadName;
   
   RunnableDemo( String name) {
      threadName = name;
      System.out.println("Creating " +  threadName );
   }
   
   public void run() {
      System.out.println("Running " +  threadName );
      try {
         for(int i = 4; i > 0; i--) {
            System.out.println("Thread: " + threadName + ", " + i);
            // Let the thread sleep for a while.
            Thread.sleep(50);
         }
      } catch (InterruptedException e) {
         System.out.println("Thread " +  threadName + " interrupted.");
      }
      System.out.println("Thread " +  threadName + " exiting.");
   }
   
   public void start () {
      System.out.println("Starting " +  threadName );
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}

public class TestThread {

   public static void main(String args[]) {
      RunnableDemo R1 = new RunnableDemo( "Thread-1");
      R1.start();
      
      RunnableDemo R2 = new RunnableDemo( "Thread-2");
      R2.start();
   }   
}