How to construct Java---inheritance

• The construction of a subclass must call the construction method of its base class.
• Subclasses can use super (parameter list) in their own construction methods to explicitly call the constructor of the base class (must be in the first of the subclass construction methods).
• Use this (parameter list) to invoke additional constructor methods for this class.
• If the construction method of the base class is not explicitly called in the constructor of a subclass, the system defaults to calling the base class without a parameter construction method.
• If the construction method of the base class is not explicitly called in the constructor of the subclass, and the base class does not have a parameterless construction method, the compilation error occurs.