2 java Questions

Help me study for my Java class. I’m stuck and don’t understand.

The problem statement for the assignment is long, but the requirements are specified in detail. Develop your solution class-by-class, module-by-module, testing at every stage. Remember to test your code frequently. Follow all class, method, and command input directions exactly as they are given in this document. Before you start coding, consider drawing out a plan for how your classes will interact and what data structures you will use. Marking Scheme: Throughout this course, we will be focusing on the complexity of algorithms and consequently, the efficiency of programs. In past CS courses your focus was on creating runnable code to specifications. This course builds on previous knowledge, but also focuses on efficiency. This will involve reducing unnecessary coding and designing or choosing good algorithm