Good Java code isn't about clever tricks — it's about consistency and readability that scales across a team. Here are the practices that separate maintainable codebases from ones that become a liability.

Favor Composition Over Inheritance

Deep inheritance hierarchies are a common source of fragility in Java codebases. Where possible, compose behavior through interfaces and delegation rather than extending classes multiple levels deep.

Use Optional Deliberately, Not Everywhere

Optional is a great tool for method return types signaling "this might not have a value" — but it's not meant for fields, parameters, or collections. Overusing it adds noise without adding safety.

Write Immutable Objects by Default

Immutable objects are inherently thread-safe and easier to reason about. Unless you have a specific reason for mutability, make fields final and provide no setters.

Let Static Analysis Catch What Code Review Misses

Tools like SpotBugs, Checkstyle, and SonarQube catch entire categories of bugs before they reach review — freeing up human reviewers to focus on design and logic rather than style nitpicks.

Test Behavior, Not Implementation

Tests tightly coupled to internal implementation details break every time you refactor, even when behavior hasn't changed. Write tests against public contracts, not private methods.

Cantonet Technologies' Java teams bring these practices to every engagement — whether we're building greenfield systems or stepping into an existing codebase.