Can we call protected method in another class?

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Yes u can. protected member can be access within the package and outside the package but within the child classes. we can use child class to use protected member outside the package but only child class object can access it.

Can I call protected method from another class?

The protected access modifier is accessible within the package. However, it can also accessible outside the package but through inheritance only. We can’t assign protected to outer class and interface. If you make any constructor protected, you cannot create the instance of that class from outside the package.

Can we call protected methods?

If a class is not final, you can use an anonymous class to call its protected method: new ClassWithProtectedMethod() { @Override protected void method() { super. method(); } }.

Can we call protected method from child class?

No because the compiler does not know whether b is an instance of B , C , or other external classes.

How can we call a protected method from abstract class?

2 Answers

  1. Create a new class that extends that abstract class SingleBrowserLocator (you will have to implement the abstract methods in it);
  2. Search for a non abstract subclass of SingleBrowserLocator that makes that method public or has other public methods that calls the protected one;

Can protected methods be overridden?

Yes, the protected method of a superclass can be overridden by a subclass. If the superclass method is protected, the subclass overridden method can have protected or public (but not default or private) which means the subclass overridden method can not have a weaker access specifier.

Can we call protected method from outside class Java?

We cannot access the protected members of a class in a class (non-subclass) that is present in a different package.

Can we extend protected class?

class is defined protected —> it cannot be extended from outside package(not visible). And if it cannot be extended then it is meaningless to keep it as protected, because then it will become default access which is allowed.

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Are protected methods Final?

1) Private methods are final. 2) Protected members are accessible within a package and inherited classes outside the package. 3) Protected methods are final.

Can constructor be protected in Java?

Access specifiers/modifiers allowed with constructors

Modifiers public, protected and, private are allowed with constructors. We can use a private constructor in a Java while creating a singleton class. The Singleton’s purpose is to control object creation, limiting the number of objects to only one.

Can we use protected variable in child class?

Protected variables can be accessed within Child Class or Child Object.

Can abstract method be static?

If you declare a method in a class abstract to use it, you must override this method in the subclass. But, overriding is not possible with static methods. Therefore, an abstract method cannot be static.

Can we use private method in abstract class?

Abstract classes can have private methods. Interfaces can’t. Abstract classes can have instance variables (these are inherited by child classes).

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.

Is private method are final?

So, to answer question 2, yes, all compilers will treat private methods as final . The compiler will not allow any private method to be overridden. Likewise, all compilers will prevent subclasses from overriding final methods.

Can member data be public?

The data members and member functions declared as public can be accessed by other classes and functions too. The public members of a class can be accessed from anywhere in the program using the direct member access operator (.) with the object of that class.

Can static methods be private?

Yes, we can have private methods or private static methods in an interface in Java 9.

Can a class be static in Java?

Classes can be static which most developers are aware of, henceforth some classes can be made static in Java. Java supports Static Instance Variables, Static Methods, Static Block, and Static Classes. The class in which the nested class is defined is known as the Outer Class.

What is protected vs private?

private: The type or member can be accessed only by code in the same class or struct . protected: The type or member can be accessed only by code in the same class , or in a class that is derived from that class .

Can we override final method in Java?

No, the Methods that are declared as final cannot be Overridden or hidden. For this very reason, a method must be declared as final only when we’re sure that it is complete. It is noteworthy that abstract methods cannot be declared as final because they aren’t complete and Overriding them is necessary.

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 a constructor be overridden?

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.

Why constructors are always public?

You make a constructor public if you want the class to be instantiated from any where. You make a constructor protected if you want the class to be inherited and its inherited classes be instantiated.

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Can constructor be static?

Java constructor can not be static

One of the important property of java constructor is that it can not be static. We know static keyword belongs to a class rather than the object of a class. A constructor is called when an object of a class is created, so no use of the static constructor.

Can inherited class access private members?

Private members of the base class cannot be used by the derived class unless friend declarations within the base class explicitly grant access to them. In the following example, class D is derived publicly from class B . Class B is declared a public base class by this declaration.

Can we declare a class as protected?

No, we cannot declare a top-level class as private or protected. It can be either public or default (no modifier). If it does not have a modifier, it is supposed to have a default access.

Can we have constructor in interface?

No, you cannot have a constructor within an interface in Java. You can have only public, static, final variables and, public, abstract, methods as of Java7.

Can interface be declared as static?

Similar to Default Method in Interface, the static method in an interface can be defined in the interface, but cannot be overridden in Implementation Classes. To use a static method, Interface name should be instantiated with it, as it is a part of the Interface only.

Can main method be abstract?

Yes, you can use the main() method in abstract class. The main() method is a static method so it is associated with Class, not with object or instance. The abstract is applicable to the object so there is no problem if it contains the main method.

Can we use final keyword in abstract class?

Yes, there may be “final” methods in “abstract” class. But, any “abstract” method in the class can’t be declared final. It will give “illegal combination of modifiers: abstract and final” error.

Can we declare local inner class as abstract?

Local Inner classes are not a member of any enclosing classes. They belong to the block they are defined within, due to which local inner classes cannot have any access modifiers associated with them. However, they can be marked as final or abstract.

Can abstract classes be public?

Abstract classes shouldn’t have public constructors because they don’t make sense. Abstract classes are incomplete, so allowing a public constructor (which anyone could call) wouldn’t work as you can’t instantiate an instance anyway.

Can return type change in overriding?

From Java 5 onwards, we can override a method by changing its return type only by abiding the condition that return type is a subclass of that of overridden method return type.

Why main () method is declared as 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. So, the compiler needs to call the main() method.

Can we extend a static class?

Just like static members, a static nested class does not have access to the instance variables and methods of the outer class. You can extend static inner class with another inner class.

What is static method in Java?

In Java, a static method is a method that belongs to a class rather than an instance of a class. The method is accessible to every instance of a class, but methods defined in an instance are only able to be accessed by that object of a class.

Can we declare method as private in Java?

Yes, we can declare the main method as private in Java. It compiles successfully without any errors but at the runtime, it says that the main method is not public.

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How can protected modifier be accessed?

How can a protected modifier be accessed? Explanation: The protected access modifier is accessible within package and outside the package but only through inheritance. The protected access modifier can be used with data member, method and constructor. It cannot be applied in the class.

Can we assign superclass object to subclass?

No. It makes zero sense to allow that. The reason is because subclasses generally define additional behavior. If you could assign a superclass object to a subclass reference, you would run into problems at runtime when you try to access class members that don’t actually exist.

Can constructors and destructors be inherited?

Constructors and destuctors are not members of the class and not inherited but instead automatically invoked if the sub class has no constructor.

What is inheritance in OOP?

Inheritance in OOP = When a class derives from another class. The child class will inherit all the public and protected properties and methods from the parent class. In addition, it can have its own properties and methods. An inherited class is defined by using the extends keyword.

How many members are there in access specifier?

Explanation: Only 3 types of access specifiers are available. Namely, private, protected and public. All these three can be used according to the need of security of members. 2.

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.

Why constructor is private in Singleton?

In singleton class, we use private constructor so that any target class could not instantiate our class directly by calling constructor, however, the object of our singleton class is provided to the target class by calling a static method in which the logic to provide only one object of singleton class is written/ …

Can we use static in abstract method?

If you declare a method in a class abstract to use it, you must override this method in the subclass. But, overriding is not possible with static methods. Therefore, an abstract method cannot be static.

Can we override static method?

No, we cannot override static methods because method overriding is based on dynamic binding at runtime and the static methods are bonded using static binding at compile time. So, we cannot override static methods. The calling of method depends upon the type of object that calls the static method.

Can a class be declared as synchronized?

The synchronized keyword can only be used on method declarations and as synchronized blocks. When used on a method declaration, it’s the same as adding a synchronized block around the contents of the method, synchronizing on this . There is nothing preventing you from synchronizing every method of a class.

Can inner class have static members?

As with instance methods and variables, an inner class is associated with an instance of its enclosing class and has direct access to that object’s methods and fields. Also, because an inner class is associated with an instance, it cannot define any static members itself.

Can we overload private methods?

Yes, we can overload private methods in Java but, you can access these from the same class.

What is polymorphism in oops?

Polymorphism is one of the core concepts of object-oriented programming (OOP) and describes situations in which something occurs in several different forms. In computer science, it describes the concept that you can access objects of different types through the same interface.