Need help writing java

Programming Assignment 3 The Public Water Commission monitors the amount of water usage, and charges $ water usage is 300 gallons or more, the customer is required to pay the water bill in person. Write a program, named waterComm.java, which inputs the water usage using an input dialog box, and reports the amount owed to the Commission in an output dialog box. In a separate output dialog box the user is warned to report in person to the $0.08 per gallon. If the amount of Commission. (Note that consumers do not always use a whole number of gallons of water)