Methods in Java are named blocks of code that perform specific tasks. Defined with 'returnType methodName(parameters) { ... }', methods encapsulate functionality for reuse. A basic method might be 'void printMessage() { System.out.println("Hello"); }'. Calling the method executes its code: 'printMessage();'. Methods enable code organization, reuse, and abstraction. Understanding method definition and invocation is fundamental to structured programming.

Mastering method basics enables you to organize code into logical, reusable units. Methods are the primary mechanism for breaking down complex problems into manageable pieces. In professional development, methods appear constantly: utility functions, business logic, calculations, and operations. For example, a 'calculateTax()' method encapsulates tax calculation logic, making it reusable and testable. Well-named methods make code self-documenting and maintainable.

By learning method fundamentals, you'll write more organized, maintainable code with clear responsibilities. Understanding method structure (return type, name, parameters, body) is essential. Methods are fundamental to Java programming and good design. Prerequisites include understanding basic syntax, variables, and program flow in Java.