What is the Thread getDefaultUncaughtExceptionHandler() in Java?

// Load Thread class
import java.lang.Thread;
// Main class
public class EdPresso implements Runnable {
   Thread thr;
   public  EdPresso() {
      thr = new Thread(this);
      //calling run() function
      thr.start();
   }
   // run() method
   public void run() {
      // printing thread name
      System.out.println("Thread is:" + thr.getName());
      /* returning the default handler that is invoked when a thread stops due to uncaught exception. */
      Thread.UncaughtExceptionHandler handler = Thread
         .getDefaultUncaughtExceptionHandler();
      System.out.println(handler);
   }
   public static void main(String[] args) {
      new  EdPresso();
   }
}