Java class hierarchy

To explicitly call the superclass constructor from the subclass constructor, we use super() . It’s a special form of the super keyword.

A subclass needs a constructor if the superclass does not have a default constructor (or has one that is not accessible to the subclass). If the subclass has no constructor at all, the compiler will automatically create a public constructor that simply calls through to the default constructor of the superclass.

A subclass needs a constructor if the superclass does not have a default constructor (or has one that is not accessible to the subclass). If the subclass has no constructor at all, the compiler will automatically create a public constructor that simply calls through to the default constructor of the superclass.

A subclass needs a constructor if the superclass does not have a default constructor (or has one that is not accessible to the subclass). If the subclass has no constructor at all, the compiler will automatically create a public constructor that simply calls through to the default constructor of the superclass.

A subclass can have its own private data members, so a subclass can also have its own constructors . The constructors of the subclass can initialize only the instance variables of the subclass. … To call a superclass constructor the super keyword is used.

A subclass can have its own private data members, so a subclass can also have its own constructors . The constructors of the subclass can initialize only the instance variables of the subclass. … To call a superclass constructor the super keyword is used.

A subclass can have its own private data members, so a subclass can also have its own constructors . The constructors of the subclass can initialize only the instance variables of the subclass. … To call a superclass constructor the super keyword is used.