How to Invoke a Parent Constructor from an Anonymous Inner Class?

How can I call a specific parent constructor from an anonymous inner class in Java?

new ParentClass() { 
    { 
        // This is an instance initializer block, 
        // and can call any method from ParentClass, 
        // but not the constructor.
        // To invoke the parent constructor, you need to provide the parent type constructor directly here.
        super("parameter"); // Calling the parent constructor
    } 
};

In Java, invoking a specific parent constructor directly from an anonymous inner class can be a bit tricky since anonymous classes don't provide a way to specify which parent constructor to call explicitly through the constructor syntax. However, you can utilize initializer blocks and delegate to the parent class constructor indirectly. Here’s a breakdown of how to achieve this effectively.

ParentClass parent = new ParentClass("parameter") { 
    { 
        // Initialization logic can go here.
    } 
}; // Creates an instance of the anonymous inner class using the parent constructor.

Causes

• Anonymous inner classes in Java cannot directly specify the parent constructor to invoke.
• Constructors of anonymous inner classes implicitly call their parent's no-argument constructor unless specified otherwise.

Solutions

• Use a constructor in the parent class that matches the parameters you wish to pass.
• Utilize an instance initializer block of the anonymous inner class to execute logic or initialize parameters after calling the parent constructor.

Mistake: Trying to call a parent constructor using 'super' inside a method rather than in the constructor or initializer block.

Solution: Always use the initializer block or construct the object directly using the parent class’s constructor.

Mistake: Assuming that the anonymous inner class can modify inherited fields before the parent constructor is called.

Solution: Understand that the parent constructor must execute first before any derived class initialization.