Can we override constructor in Java?

It does not have a return type and its name is same as the class name. But, a constructor cannot be overridden. If you try to write a super class's constructor in the sub class compiler treats it as a method and expects a return type and generates a compile time error.

How do you overwrite a constructor in Java?

A constructor belongs to the class in which it is declared. A sub class is a different class and must have its own constructor. So, constructors simply can't be overridden.

Can default constructor be overridden in Java?

Default Constructor (no-arg constructor)

Programmer also can override default constructor in class.

Can constructor be overloaded vs overridden?

Neither. Constructors are different from methods. You overload a constructor by writing multiple constructors in the same class, not in inherited classes. And constructors aren't subject to overriding.

Can a constructor be final?

Java constructor can not be final

One of the important property of java constructor is that it can not be final. As we know, constructors are not inherited in java. Therefore, constructors are not subject to hiding or overriding.

Can We Override Constructor ​in Java? | Java Interview Question

Can constructor be static?

No, we cannot define a static constructor in Java, If we are trying to define a constructor with the static keyword a compile-time error will occur. In general, static means class level. A constructor will be used to assign initial values for the instance variables.

Can a constructor be abstract?

You can't have an abstract constructor, as abstract means you need to provide the implementation for that at some point of time in your subclass. But you cannot override constructor. There will be no point in having an abstract constructor : Since the constructor needs to be of the same name as of class.

Can we override a constructor if yes how?

Constructor looks like method but it is not. It does not have a return type and its name is same as the class name. But, a constructor cannot be overridden. If you try to write a super class's constructor in the sub class compiler treats it as a method and expects a return type and generates a compile time error.

Can we override the private methods?

No, we cannot override private or static methods in Java. Private methods in Java are not visible to any other class which limits their scope to the class in which they are declared.

Can we override static method?

Overloading is the mechanism of binding the method call with the method body dynamically based on the parameters passed to the method call. Static methods are bonded at compile time using static binding. Therefore, we cannot override static methods in Java.

Can we overload constructor?

Constructors can be overloaded in a similar way as function overloading. Overloaded constructors have the same name (name of the class) but the different number of arguments. Depending upon the number and type of arguments passed, the corresponding constructor is called.

Can we overload main method?

Yes, we can overload the main method in Java, but When we execute the class JVM starts execution with public static void main(String[] args) method.

Can constructor be private?

Yes, we can declare a constructor as private. If we declare a constructor as private we are not able to create an object of a class. We can use this private constructor in the Singleton Design Pattern.

Can we overload constructor in derived class?

Since the constructors can't be defined in derived class, it can't be overloaded too, in derived class.

Can we override final method in Java?

You can declare some or all of a class's methods final. You use the final keyword in a method declaration to indicate that the method cannot be overridden by subclasses. The Object class does this—a number of its methods are final .

Can we override abstract method in Java?

A subclass must override all abstract methods of an abstract class. However, if the subclass is declared abstract, it's not mandatory to override abstract methods.

Can we overload final method?

Can We Override a Final Method? No, the Methods that are declared as final cannot be Overridden or hidden.

Can abstract method be overridden?

An abstract method is a method that is declared, but contains no implementation. you can override both abstract and normal methods inside an abstract class. only methods declared as final cannot be overridden.

Can method be declared static?

Static methods

When a method is declared with the static keyword, it is known as the static method. The most common example of a static method is the main( ) method. As discussed above, Any static member can be accessed before any objects of its class are created, and without reference to any object.

Can we call default constructor explicitly?

Is it possible to call constructor and destructor explicitly? Yes, it is possible to call special member functions explicitly by programmer.

Can we inherit static method in Java?

Static methods do not use any instance variables of any object of the class they are defined in. Static methods take all the data from parameters and compute something from those parameters, with no reference to variables. We can inherit static methods in Java.

Why main method is static?

Why the main () method in Java is always static? Java main() method is always static, so that compiler can call it without the creation of an object or before the creation of an object of the class. In any Java program, the main() method is the starting point from where compiler starts program execution.

Can we use this () and super () in a constructor?

If we include “this()” or “super()” inside the constructor, it must be the first statement inside it. “this()” and “super()” cannot be used inside the same constructor, as both cannot be executed at once (both cannot be the first statement). “this” can be passed as an argument in the method and constructor calls.

Can we declare interface as final?

If you make an interface final, you cannot implement its methods which defies the very purpose of the interfaces. Therefore, you cannot make an interface final in Java. Still if you try to do so, a compile time exception is generated saying “illegal combination of modifiers − interface and final”.

Can we create immutable class in Java?

Immutable class in java means that once an object is created, we cannot change its content. In Java, all the wrapper classes (like Integer, Boolean, Byte, Short) and String class is immutable. We can create our own immutable class as well.