Code Smells made-easy

Learn to identify long methods (over ten lines) as a code smell and apply practical refactoring techniques—extract method, replace temp with query, and method object—to improve readability and maintainability.

Identify signs of a large class and apply extract class, extract subclass, extract interface, and duplicate observed data to decompose it into cohesive units. Move related code incrementally and test.

Explore primitive obsession in software, where basic types replace proper objects, and learn refactoring steps like replace data value with object and introduce parameter object for clearer, flexible code.

Identify and fix long parameter lists by replacing parameters with method calls, preserving whole objects, or introducing a parameter object.

Identify data clumps as identical groups of variables that recur across code and apply refactoring, like extract class or introduce parameter object, to improve organization.

Identify telltale signs of sprawling switch statements in object oriented design. Refactor using extract method and replace type code with subclasses to embrace polymorphism.

Explore temporary fields as a code smell in object oriented programming, and learn refactoring techniques—extract class and introduce null object—to improve clarity, cohesion, and testability.

Identify refused bequest in inheritance where a subclass uses only a tiny portion of what it inherits, and fix it with delegation or extracting a superclass.

unify duplicate classes with different interfaces by standardizing method names and signatures, extracting common functionality, and refactoring toward a single, maintainable code base.

Divergent change is a code smell where one class changes for many unrelated reasons. Refactor by extracting focused classes to uphold the single responsibility principle, reducing maintenance effort and duplication.

Tackle shotgun surgery as a code smell by identifying scattered responsibilities and refactoring with move method, move field, or create new class.

Explore how parallel inheritance hierarchies create code smells, duplications, and maintenance burdens, and learn refactoring strategies like move methods and move fields to untangle them.

Investigate how excessive comments can signal deeper issues in code and learn refactoring techniques like extract variable, extract method, rename method, and introduce assertion.

Identify and reduce duplicate code through refactoring techniques such as extracting methods, pulling up shared fields, and using template methods. Improve maintainability, reduce code size, and lower bugs.

Identify lazy classes and apply inlining or collapsing hierarchies to streamline code, improve maintenance and performance, while balancing future needs and api stability.

Refactor data classes by encapsulating data and moving behavior into the class, using private fields and controlled access. Boost maintainability and reduce code duplication.

Identify dead code like unused variables, ignored parameters, and unreachable branches using IDEs and static analysis; then remove or refactor to improve readability, maintainability, and performance.

Speculative generality builds code for future features that rarely materialize, creating dead weight and false dependencies. Use analysis tools to remove unused code and simplify structures to reduce maintenance.

Recognize feature envy, where a method excessively accesses another object's data, and fix by moving the method into the data's class or extracting smaller methods to co-locate logic.

Address inappropriate intimacy, a code smell, by enforcing boundaries between classes, reducing tight coupling, and moving methods and fields to improve reusability and maintainability.

Explore how message chains create fragile dependencies and how hide delegate, extract method, and move method untangle them to yield cleaner, more maintainable, testable code with easier testing in isolation.

Identify classes whose methods merely delegate and apply the remove middleman refactoring to let callers talk directly to the working class. Expect a slimmer, clearer code base and performance boost.

Learn how to extend an incomplete library without rewriting it using a foreign method and local extension, documenting changes and weighing maintenance and complexity.