java

keep it simple pls

variables: first: a String variable for the first name; last: a String variable for the last name; grade: a double variable for the grade. studentNumber: an integer variable that is incremented when a student is created. 10. Add a constructor 1 that do nothing. 11. Add a constructor 2 that takes 3 parameters to initialize the instance variables. 12. Create a showStudent method that displays the information of one student (the instance variables). 13. Create a TestStudent class with main method in which: a. Create an object S1 with the first constructor. b. Create an object S2 with the second constructor. c. Call showStudent method for S1 and S2. d. Add the instruction S3=S2. Show the references of S1, S2 and S3