Object Creation – Explained

On executing 

Car bmw = new Car();Car benz=new Car();Car audi =benz;

References created = 3

Objects created = 2

When Car bmw = new Car() is called the following happens

• Only a reference is created when a variable is defined of a class type. Memory for that variable is allocated only when new() is used.
• JVM allocates enough memory on the heap for  the defined instance variables
• Variables are initialized to their default values
• Initialization blocks are executed
• Constructor of the class is called which in turn delegates the call to its super class and the delegation continue until it reaches the Object class

Class Loading 

Refer  Image : Class Loading

• 3 phases in class loading
  • Physical loading
    • Required class files are loaded from the system classpath.
    • Basic memory structure of the class is calculated at this stage
  • Linking
    • Verifying
      • Bytecode verification through class loader.
    • Preparing
      • Prepares various data-structures for fields, methods and interface implementation by the class
    • Resolving all references
      • SuperClasses – Abstract, non-Abstract
      • Interfaces
      • Variables
      • Types defined in method signature
      • Local variables defined in methods
  • Initializing
    • Static blocks and static variables are initialized
    • Due to lazy loading few of the variables can be initialized only on demand