The difference between Classes, Objects, and Instances

Question

What is a class, an object and an instance in Java?

Answer 1

Class is Data Type,You use this type to create object.

• Instance is Logical but object is Physical means occupies some memory.

• We can create an instance for abstract class as well as for interface, but we cannot create an
  object for those.

• Object is instance of class and instance means representative of class i.e object.

• Instance refers to Reference of an object.

• Object is actually pointing to memory address of that instance.

• You can’t pass instance over the layers but you can pass the object over the layers

• You can’t store an instance but you can store an object

• A single object can have more than one instance.

• Instance will have the both class definition and the object definition where as in object it will have only the object definition.

Syntax of Object:

 Classname var=new Classname();

But for instance creation it returns only a pointer refering to an object, syntax is :

 Classname varname;