Question: Can we Override or Overload static methods in the java?

  • Overriding: It is mainly related to the run-time polymorphism. The subclass or the derived class offers a specific implementation about the method in a superclass or on the base class at the runtime.
  • Overloading: It is mainly related to compiling time which is also known as static polymorphism. Such kind of feature allows various methods to have a similar name, but diverse signatures, a particular number of input parameters along with the kind of input parameters.
  • Can we overload the methods of static? Here, the answer is ‘Yes’. We may have two and more static methods having a similar name, but differences in the input parameters
  • Can we also override static methods in the java? We may also declare the static methods with a similar signature in the subclass, but it is not considered overriding as there will not be any kind of the run-time polymorphism. So, the answer is ‘No’. The Static methods cannot get overridden for the reason that the method overriding usually occurs in the context of dynamic such as i.e. runtime and also the lookup of methods. The Static methods with their name are also looked up statically such as i.e. at compile-time.

Question: Why the key method of java is static?

Yes, the static method is key in java as otherwise there will also be ambiguity: that constructor must be called? Particularly when your class appears like this:

Should JVM call the new JavaClass or (int)? What must it pass for x? In case not, should JVM instantiate of the JavaClass devoid of running any kind of method for constructor? As this will special-case for the complete class – at times, you have a chance that has not been initialized; you need to check for each method which may also be called. There are usually various edge cases as well as ambiguities that make sense for JVM to get instantiate a class before the entry point. This is the reason that the key point is static in java.

Question: What will happen if you will remove the static modifier from the key method?

 The Program compiles effectively, however at the time of runtime throws some error which says “NoSuchMethodError”.

Question: What is the scope of the variables in Java for mentioned cases?

  • Member Variables which is Class Level Scope: variables member should be declared inside the class and outside any of function. These will be accessed directly anywhere in the class
  • Local Variables that is also known as Method Level Scope: The Variables that are declared inside the method with the level scope and may not be accessed outside method.
  • Loop Variables or the Block Scope: A variable which is declared inside the pair of brackets “{” and “}” in the method which has scope within the brackets.

Question: What is the meaning of “this” keyword in java?

With the instance method or with the constructor, this is mainly the reference to current object — where the object whose method and the constructor are being called. You may even refer to any of the members of the current object from the instance method or the constructor with the use of this

Use of “this” keyword

– It is used to refer to the current class of the instance variable.

– It helps to invoke the current class constructor.

– It may also be passed as an argument in the method call.

– It may also be passed as an argument in the constructor call.

– It is also used to return the instance of the current class.

– It is used to invoke the current class method such as implicitly

Question: What does abstract class means in java? How the abstract classes are different or similar in Java from C++?

The Abstract classes are main classes which include one or more methods of abstract. The abstract method is the method which is declared, but it does not contain any implementation. The Abstract classes might not be instantiated, and it might need subclasses to offer implementations for abstract methods.

– C++, in Java, it is an instance of an abstract class which could not be created, we may also have references to the abstract class type.

– C++, abstract class may also consist constructors in the Java. And also the constructor of the abstract class is known when an instance of the inherited class gets created

– Also in Java, we may even have an abstract class that is devoid of any method of abstract. It allows us to create the classes which cannot get instantiated but may just be inherited.

– The Abstract classes may even have the final methods or the methods which may not be overridden. For instance, the following program usually compiles and it also runs fine.

Question: Can the main method be overloaded?

The key method in Java is mainly about no additional terrestrial method. Apart from the truth that main is only like some other method & it may also get overloaded similarly, JVM usually looks for a method for the signature to launch the program.

– The normal and the key method always act as the entry point for JVM to begin the program execution.

– We may also overload the key method in Java. However, the program does not execute the overloaded key method while we run the program; we should call the overloaded main method and that also from the actual method.

Question: What do we mean by object cloning?

The concept of Object cloning means creating the exact and precise copy of the original object. When the class requires supporting the object cloning, it should implement the interface of java.lang.Cloneable and override clone or the method from the Object class. Moreover, Syntax of the clone method is as mentioned below:

Protected Object clone that throws CloneNotSupportedException

If the object’s class does not implement the interface of Cloneable then it will throw an exception of ‘CloneNotSupportedException’.

Question: Do we have access to override the private methods in Java?

The answer is No; the private method will not be overridden as it is not visible from any different class.