Protecting a constructor prevents the users from creating the instance of the class, outside the package. During overriding, when a variable or method is protected, it can be overridden to other subclass using either a public or protected modifier only. Outer class and interface cannot be protected.
Should I use protected Java?
Most of the time, it is dangerous to use protected because you break somewhat the encapsulation of your class, which could well be broken down by a poorly designed derived class.
What does it mean to be protected in Java?
In Java, protected means that the member can be accessed by any class in the same package and by subclasses even if they are in another packages.
What does the protected modifier accomplish?
protected access modifier in Java
The protected access modifier in Java denotes that the variable or a method is accessible to its subclasses but private to all other classes outside the current package. It allows access to the class itself, subclasses and all classes in the same package to access the members.
What is the purpose of the public private and protected keywords within Java?
Public, protected, and private are the keywords used when you declare a variable or a method. Each one tells Java how much to share about that variable or method.
Why do we use protected?
So if we want data members to be accessible to only derived classes and not privately or publicly accessible, then we can use protected. – Protected is similar to private. – It makes class member inaccessible outside the class, but the members can be accessed by any subclass of that class.
Should I use protected or private?
Use protected if subclasses will use the method/variable, otherwise use private. Specifically, if subclasses would have to re-define a very similar private variable in the parent, just make it protected.
What is difference between public/private and protected in Java?
Public members can be accessed from the child class of the same package. Private members cannot be accessed from the child class of the same package. Protected members can be accessed from the child class of the same package. Package members can be accessed from the child class of the same package.
Can we override a protected method in Java?
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.
Who can access protected method Java?
2. The protected Keyword. While elements declared as private can be accessed only by the class in which they’re declared, the protected keyword allows access from sub-classes and members of the same package.
What is protected method?
A protected method is like a private method in that it can only be invoked from within the implementation of a class or its subclasses. It differs from a private method in that it may be explicitly invoked on any instance of the class, and it is not restricted to implicit invocation on self .
What is difference between private and protected?
Things that are private are only visible within the class itself. Things that are protected are visible in the class itself and in subclasses.
What is difference between public and protected?
The difference between public and protected is that public can be accessed from outside class but protected cannot be accessed from outside class.
When should a method be private?
The rule is that a method should be made provided unless it is needed. One of the main reasons for this is that in a future release of an API etc., you can always make a private function public, but you can almost never make a previous public function private without breaking existing code.
What is private protected?
The private protected keyword combination is a member access modifier. A private protected member is accessible by types derived from the containing class, but only within its containing assembly. For a comparison of private protected with the other access modifiers, see Accessibility Levels.
Can a Java class be private or protected?
No, we cannot declare a top-level class as private or protected. It can be either public or default (no modifier).
Why do we use super in Java?
The super keyword refers to superclass (parent) objects. It is used to call superclass methods, and to access the superclass constructor. The most common use of the super keyword is to eliminate the confusion between superclasses and subclasses that have methods with the same name.
What’s the difference between a protected method and a private method?
Protected methods are a balance between public and private methods. They are similar to private methods in that they cannot be accessed in the public scope. Neither the client nor the program can invoke them. However, objects of the same class can access each other’s protected methods.
When should a method be private vs public?
Which one we should use? We should use public access modifier if we want to make the method or property visible from anywhere, other classes, and instances of the object. Use the private access modifier if you want to make the method or property visible in its own class only.
Can I call protected method?
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 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.
How do you call a protected method in Java?
Example 2
- class A {
- protected String msg=”Try to access the protected variable outside the class within the package”;
- }
- public class ProtectedExample2 {
- public static void main(String[] args) {
- A a=new A();
- System.out.println(a.msg);
- }
What is the difference between private and protected inheritance?
protected inheritance makes the public and protected members of the base class protected in the derived class. private inheritance makes the public and protected members of the base class private in the derived class.
What is protected access specifier in Java?
protected: The protected access modifier is specified using the keyword protected. The methods or data members declared as protected are accessible within the same package or subclasses in different packages.
Why we Cannot override private method?
You cannot override a private or static method in Java. If you create a similar method with same return type and same method arguments in child class then it will hide the super class method; this is known as method hiding. Similarly, you cannot override a private method in sub class because it’s not accessible there.
What is the use of private method in Java?
The private keyword is an access modifier used for attributes, methods and constructors, making them only accessible within the declared class.
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.
What is protected internal?
protected internal: The type or member can be accessed by any code in the assembly in which it’s declared, or from within a derived class in another assembly.
What is difference between private member and protected member?
Private members are accessible within the same class in which they are declared. Protected members are accessible within the same class and within the derived/sub/child class. Private members can also be accessed through the friend function. Protected members cannot be accessed through the friend function.
What is Java garbage?
Java garbage collection is the process by which Java programs perform automatic memory management. Java programs compile to bytecode that can be run on a Java Virtual Machine, or JVM for short. When Java programs run on the JVM, objects are created on the heap, which is a portion of memory dedicated to the program.
What is Polymorphism in Java?
In Java, polymorphism refers to the ability of a class to provide different implementations of a method, depending on the type of object that is passed to the method. To put it simply, polymorphism in Java allows us to perform the same action in many different ways.
What is the difference between super and super () in Java?
The super keyword in Java is a reference variable that is used to refer parent class objects. The super() in Java is a reference variable that is used to refer parent class constructors. super can be used to call parent class’ variables and methods. super() can be used to call parent class’ constructors only.
What are the 3 uses of super keyword?
Usage of Java super Keyword
super can be used to refer immediate parent class instance variable. super can be used to invoke immediate parent class method. super() can be used to invoke immediate parent class constructor.
Why main method is always public in Java?
Why is main method public in Java? We know that anyone can access/invoke a method having public access specifier. The main method is public in Java because it has to be invoked by the JVM. So, if main() is not public in Java, the JVM won’t call it.
Why is Java called WORA?
Write once, run anywhere (WORA) is a term that refers to a particular program’s supposed ability to run on all common OSs (operating systems). The term, sometimes also expressed as write once, run everywhere (WORE), was originally coined by Sun Microsystems in reference to Java.
What is difference between public and protected in Java?
Public members can be accessed from the child class of the same package. Private members cannot be accessed from the child class of the same package. Protected members can be accessed from the child class of the same package. Package members can be accessed from the child class of the same package.
What is difference between private and protected in Java?
The private modifier specifies that the member can only be accessed in its own class. The protected modifier specifies that the member can only be accessed within its own package (as with package-private) and, in addition, by a subclass of its class in another package.
How do I access protected variables?
Protected Access Modifier – Protected
Variables, methods, and constructors, which are declared protected in a superclass can be accessed only by the subclasses in other package or any class within the package of the protected members’ class. The protected access modifier cannot be applied to class and interfaces.
What is a protected method?
A protected method is like a private method in that it can only be invoked from within the implementation of a class or its subclasses. It differs from a private method in that it may be explicitly invoked on any instance of the class, and it is not restricted to implicit invocation on self .