Java programming

Write an application (GradeAve) that takes in from the teacher the grades for students and comes up with a class average. using the jOptionPane clas , have the teacher input (using a window) each grade as an integer. The program should allow the teacher to enter up to ten grades (there are only ten students in the class), but there also may be less than ten. Have the teacher enter a sentinel value when he/she is done entering grades (if it is below 10). Use a do loop for this problem. After the grades have been entered, display the class average. The average should be precise to two decimal places. [Note: test this to make sure it works right!!! Dont just enter random grades, enter grades where you KNOW what the average should beand make sure you get that average.]