How to print an array of strings with threads

I have a String array:

String[] messages = new String[]{"aaaa", "bbbb", "cccc"};

How do I print every value of it by separate threads? Every value is one thread. Threads are created the same amount as strings in array. Thanks!

I have only one class of Thread for this:

class Worker extends Thread{
}

Iterate over each element of the array and construct a Worker from each one. The Worker class should override the run method to print the String.

class Worker extends Thread{
    private String message;
    public Worker(final String message){
       this.message = message;
    }
    @Override
    public void run(){
      System.out.println(message);
    }
}
public class Main {
    public static void main(String[] args){
       String[] messages = new String[]{"aaaa", "bbbb", "cccc"};
       for(final String message: messages){
         new Worker(message).start();
       }
    }
}

Executor service rather than extending Thread

The Executors framework was added to Java to relieve us app programmers of juggling threads. See tutorial.

Get an executor service from Executors.

ExecutorService es = Executors.newCachedThreadPool() ; 

Write your task as implementation of Runnable.
Notice that we are not extending Thread, in contrast to your code.

String[] messages = new String[]{ "aaaa" , "bbbb" , "cccc" } ;
for( String message : messages ) 
{
    es.submit(
         () -> { System.out.println( message ) ; }
    ) ;
}

In that code above, we use lambda syntax. You could just as well use traditional syntax.

When run using a thread pool of more than one thread, the order in which the tasks are executed is indeterminate. For example, when run the output may appear like this:

>aaaa

>cccc

>bbbb

String[] messages = new String[]{ "aaaa" , "bbbb" , "cccc" } ;
for ( String message : messages )
{
    es.submit(
            new Runnable()
            {
                @Override
                public void run ( )
                {
                    System.out.println( message );
                }
            }
    );
}

By the way, lists are generally more convenient than arrays in Java.

List< String > messages = List.of( "aaaa" , "bbbb" , "cccc" ) ;
for( String message : messages ) 
{
    es.submit(
         () -> { System.out.println( message ) ; }
    )
}

See this entire example class run live at IdeOne.com.

import java.util.*;
import java.lang.*;
import java.io.*;

import java.time.Instant ;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		System.out.println( "Starting. " + Instant.now() );
		
        ExecutorService es = Executors.newCachedThreadPool();

        List < String > messages = List.of( "aaaa" , "bbbb" , "cccc" );
        for ( String message : messages )
        {
            es.submit(
                    ( ) -> { System.out.println( message ); }
            );
        }

		System.out.println( "Tasks submitted to executor service. " + Instant.now() );
        try
        {
            Thread.sleep( TimeUnit.SECONDS.toMillis( 3 ) );
        }
        catch ( InterruptedException e )
        {
            e.printStackTrace();
        }
        System.out.println( "Done. " + Instant.now() );
        
	}
}