基于组合框选择更新文本框

I am making a little program that calculates the calories burned based on 5 different physical activities selected from a combobox in java. the user is given 5 options: bowling, archery, lacross, wrestling, and painting. here is the website with the given numbers calculated, and the user enters his weight and how long he worked out, in either minutes or hours, and when he/she hits calculate it should display the total calories burned. I am making a little program that calculates th