Java Constructor Chain

The way how java constructors are chained has three parts and is applied repeatedly for each successive constructor that is invoked:

• If the first statement of a constructor is an ordinary statement—i.e., not a call to this( ) or super( )—Java inserts an implicit call to super( ) to invoke the default constructor of the superclass. Upon returning from that call, Java initializes the instance variables of the current class and proceeds to execute the statements of the current constructor.

• If the first statement of a constructor is a call to a superclass constructor via super( ), Java invokes the selected superclass constructor. Upon its return, Java initializes the current class's instance variables and proceeds with the statements of the current constructor.

• If the first statement of a constructor is a call to an overloaded constructor via this( ), Java invokes the selected constructor, and upon its return, simply proceeds with the statements of the current constructor. The call to the superclass's constructor has happened within the overloaded constructor, either explicitly or implicitly, so the initialization of instance variables has already occurred.