Let's say you've created a class called MyClass.java (in Eclipse in this example). 

In this example, the MyClass.java class is in the com.sample.main package. There is a public class called "MyClass", a public method called "main", and a variable called "date".  The "date" variable is returned, so that it can be used (such as in a JSP page).

package com.sample.main;

import java.util.Date;

public class MyClass {
   public static void main(String args[]) {
      Date date = new Date();
      System.out.println("Current date and time is : " + date.toString());
   }
}

Running this class should return something like this.

The current date and time is Tue Jan 29 09:14:51 CDT 2021

Here is how you can customize the date and time output.

package com.sample.main;

import java.util.Date;
import java.text.*;

public class MyClass {
   public static void main(String args[]) {
      Date date = new Date();
      SimpleDateFormat ft = new SimpleDateFormat ("MM/dd/yyyy 'at' hh:mm:ss a");
      System.out.println("Current date and time is : " + ft.format(date));
   }
}

Which should return something like this.

The current date and time is 01/29/2021 at 09:17:45 AM