Calling methods on objects in Java uses dot notation: 'object.method()'. Instance methods operate on specific object instances, accessing their fields and state. For example, 'player.jump();' calls the jump method on a specific player object. Each object has its own state, so methods can behave differently for different instances. Understanding instance method calls is fundamental to object-oriented programming and working with objects effectively.

Mastering object method calls enables you to leverage encapsulation and work with stateful objects. Being able to invoke methods on specific instances is central to OOP. In professional development, instance methods appear everywhere: calling list operations, file operations, stream processing, UI interactions. For example, 'cart.addItem(item);' adds an item to a specific cart, while 'file.write(data);' writes to a specific file. Understanding 'this' (implicit parameter) helps you reason about instance methods.

By learning instance method invocation, you'll understand how objects encapsulate behavior and state together. Knowing when to use instance versus static methods is crucial for good design. This knowledge is fundamental to working with Java's object model. Prerequisites include understanding classes, objects, and basic method concepts in Java.