Java Implicit Super Constructor Error: How to Fix \'Implicit super constructor... is undefined for default constructor\'?

Java Error: Implicit Super Constructor Undefined for Default Constructor

Q: Default Constructor Error with Subclass and Abstract Base Class

A Java developer encounters an error stating "Implicit super constructor BaseClass() is undefined for default constructor." after removing redundant constructors from subclasses. They wonder if it's possible to remove the constructors while still adhering to the template method pattern.

A: Construction and Default Constructors

The error arises because the base class (BaseClass) declares a constructor (public BaseClass(String someString)), disabling the default constructor (without arguments). When removing the constructor from the subclass (ACSubClass), the compiler inserts an implicit call to the no-argument constructor of the base class (super()) via the default constructor. Since BaseClass doesn't have a no-argument constructor, this is illegal.

Possible Solutions:

1. Remove Constructor from BaseClass: Allow the base class to have only the default constructor, which subclasses can inherit.
2. Declare No-Argument Constructor in BaseClass: Add a no-argument constructor to the base class, either as the only constructor or alongside other constructors.

However, these solutions may not be feasible if the base class requires constructor arguments.

Additionally, consider refactoring the design:

• Use a Factory to Create Subclass Instances: Create a factory class that handles the creation of subclasses with the necessary arguments.
• Pass Arguments to the getName() Method: Design the getName() method in a way that allows for arguments to customize the returned name value.

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