Java Classes And Instance 

01. What is Class ?

Think of a Class as a blueprint, template, or a recipe. It is not a real thing yet; it just describes what something should look like and do.

As shown in the first image, a class is like a 3-compartment box that holds three things:

1. Name: What the class is called (e.g., Student, Car, Circle).

2. Variables (Attributes): The data or information about it (e.g., a student has a name and a gpa).

3. Methods (Behaviors): What it can do (e.g., a student can getName() or setGpa()).

 02.What is an Instance (Object)?

An Instance (also called an Object) is the real thing created using that blueprint. Look at the second image:

• The blueprint is Student.

• From that one blueprint, we created two real students: paul and peter.

• They both have the same structure (name and gpa), but their actual information is different (Paul's GPA is 3.5, while Peter's GPA is 3.9).