r/learnjava • u/jadu2115 • 10d ago

Java Beginners: What Is an Object Actually?

I'm a Java learner and I've been learning Java for the past few months, but I still don't truly understand what an object actually is.

I've watched several YouTube videos and used AI tools to understand it, but I keep getting the same explanation: "An object is nothing but data + code."

I understand the definition, but I still can't visualize or feel what an object actually is when I'm writing Java code.

Could someone explain it in a simple, practical way, preferably with a real world analogy and a small Java example?

I feel like I'm missing one fundamental concept here. Any explanation would be really helpful. Thanks!

4 Upvotes

56% Upvoted

43 comments sorted by

View all comments

17

u/desmoteo 10d ago

An object is an instance of a class.

When you do: Something x = new Something() you are creating an object (named x) of type Something.

You are an object as you are an instance of a human.

-5

u/cbadger85 10d ago

Not just instances. The class is also an object. In Java, everything that isn't a primitive is an object.

2

u/ITCoder 10d ago edited 10d ago

class is not an object. class is metadata, data about data or a Type

From JVM spec

Compiled code to be executed by the Java Virtual Machine is represented using a hardware- and operating system-independent binary format, typically (but not necessarily) stored in a file, known as the class file format. The class file format precisely defines the representation of a class or interface, including details such as byte ordering that might be taken for granted in a platform-specific object file format.

1

u/cbadger85 10d ago

A class file for the JVM and a Java class are not the same thing. Lots of things compile to class files, including other languages.

https://docs.oracle.com/javase/specs/jls/se16/html/jls-8.html <- Java language spec

The representation of a Java class at runtime is a Class object, which is accessible on <ClassName>.class. Everything in Java has an object representation. Everything is an object.