Methods

The Big Picture

Methods are named blocks of code that perform actions. They accept parameters, do work, and optionally return a value.

• Organize code into reusable, testable pieces
• Signature: name + parameter types (not return type)
• void methods return nothing; others must return a value

Good methods do one thing well and have descriptive names.

How It Works

Method calls use the call stack. Each call creates a frame holding local variables and return address.

• Java passes primitives by value (copy)
• Java passes object references by value (ref is copied)
• static methods belong to the class, not an instance
• Overloading: same name, different parameter types/count

In the Java Landscape

Methods are how Java implements behavior in OOP.

• Java 8 added default methods in interfaces
• Varargs (Java 5+): void log(String... msgs)
• Records auto-generate accessor methods (Java 16+)
• Method references: String::length (Java 8+)
• final methods can't be overridden by subclasses

Pitfalls and Best Practices

• Keep methods short - 20 lines max is a good target
• One responsibility per method (Single Responsibility)
• Use @Override when overriding to catch typos
• Avoid side effects - prefer returning results
• Validate parameters at method entry (fail fast)
• Name with verbs: calculateTotal(), findUser()