Can we initialize the final variable in the constructor?
A final blank variable can be initialized within the instance initializer block or within the constructor. If you have more than one constructor in your class, it must be initialized in all of them; otherwise, a compile-time error will be generated. A final blank static variable can be initialized within the static block.
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What happens if we use Final keyword with variable and method?
What is the final keyword in Java? Java’s final keyword is a non-access specifier that is used to restrict a class, variable, and method. If we initialize a variable with the final keyword, we cannot modify its value. If we declare a method as final, then it cannot be overridden by any subclass.
Can final be used on method parameters and local variables?
In Java, you can qualify local variables and method parameters with the final keyword. If you do, you won’t be able to reassign x and qwerty in the method body. This practice pushes your code in the direction of immutability, which is generally considered an advantage.
Can you use methods in a constructor?
It shouldn’t: calling the instance method in the constructor is dangerous because the object isn’t fully initialized yet (this mostly applies to overridable methods). Complex processing in the constructor is also known to have a negative impact on testability.
Can we declare the final variable inside the method?
As a general rule, a final variable should be initialized only once. Other initializations are not allowed.
Can you use this() and super() both in a constructor to justify the reason with an example?
both this() and super() cannot be used together in the constructor. this() is used to call the default constructor of the same class. It must be the first declaration inside the constructor. super() is used to call the default constructor of the base class. It must be the first declaration inside the constructor.
When to call an overridable method from a constructor?
Like… When you call a nullable method from a constructor, there is a risk that a child class will override that method and access the attributes it declares. When the constructor is executed, the overridden method is called, but the attributes declared in the child class are not yet initialized.
How to create private method in java constructor?
Fred Kleinschmidt wrote: For any method called in your constructor that is overridden or public, create a private method to do that functionality and call the private methods of your constructor and the public or overridden methods. For example, let’s take AddItem:
What happens when the Base Constructor calls overrideme?
Here, when the Base constructor calls overrideMe, the Child hasn’t finished initializing the final int x and the method gets the wrong value. This will almost certainly lead to crashes and errors. Constructors with many parameters can lead to poor readability and there are better alternatives.
What happens when you override a method in Java?
If you call methods in your constructor that override subclasses, it means you’re less likely to reference variables that don’t already exist if you split your initialization logically between the constructor and the method.