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Style Guidelines

You only write code once, but read it many times. Having clean, organized, legible, intuitive, and understandable code is important for those who read it: whether it be for debugging purposes (yourself, a peer, or a TA), for style grades (a TA), or even for judging your coding abilities and organization (a potential employer/co-worker). Yes, your code may run and solve a given problem whether it is organized or not. But, writing your code in a clean and organized way from the start will benefit you in the long run.

General Guidelines

Code must compile: Any code you submit must compile. If it does not compile, we won’t grade the assignment and you will lose all the points for the assignment.

Don’t repeat yourself (DRY): If you find yourself writing the same or similar code two or more times, consider whether it could be put in a separate method.

Break up large methods: If a method has many parts doing distinct and non-overlapping functions, consider breaking up the method.

Don’t rewrite existing code: The Java standard libraries provide implementations of a great number of methods and data structures: use them! The java.util package will prove especially useful in this course.

Comments: Comment your code where necessary e.g. complicated functions, specifying method behaviors, stating invariants. When documenting methods, write Javadoc. Within methods, good style and good variable names are usually enough: don’t over-comment.


You should adhere to the Google Java Style Guide with the following exceptions:

The easiest way to format your code correctly is to understand the style guideline and get used to seeing code that looks good. However, most modern IDEs and text editors have code formatters, which we encourage you to configure and use.

Upon submission, our grader will lint your code and point out anything wrong with your style, which you should fix.

OO (Object-Oriented) Concerns

Avoid public fields: Use getters and setters instead. If a class Point has an instance variable x and you are working with a Point point, you should not find yourself writing point.x. Instead, declare x as a (package-)private variable, and write a getter method, point.getX(). One exception in which this rule may be waived is if the variable x is marked as final.

Use appropriate modifiers for all types: In general, restrict visibility as much as possible. If need a refresher on modifiers (like protected, final, static), refer to the Oracle pages on access-level modifiers and instance/class members.