Which access specifier is by default in class data member and member function private/public protected private and public?
You must have seen public, private and protected keywords while practising java programs, these are called access modifiers. An access modifier restricts the access of a class, constructor, data member and method in another class. In java we have four access modifiers: Show
1. Default access modifierWhen we do not mention any access modifier, it is called default access modifier. The scope of this modifier is limited to the package only. This means that if we have a class with the default access modifier in a package, only those classes that are in this package can access this class. No other class outside this package can access this class. Similarly, if we have a default method or data member in a class, it would not be visible in the class of another package. Lets see an example to understand this: Default Access Modifier Example in Java
In this example we have two classes, Test class is trying to access the default method of Addition class, since class Test belongs to a different package, this program would throw compilation error, because the scope of default modifier is limited to the same package in which
it is declared. Test.java Output: Exception in thread "main" java.lang.Error: Unresolved compilation problem: The method addTwoNumbers(int, int) from the type Addition is not visible at xyzpackage.Test.main(Test.java:12)2. Private access modifierThe scope of private modifier is limited to the class only.
Let’s see an example to understand this: Private access modifier example in javaThis example throws compilation error because we are trying to access the private data member and method of class ABC in the class Example. The private data member and method are only accessible within the class. class ABC{ private double num = 100; private int square(int a){ return a*a; } } public class Example{ public static void main(String args[]){ ABC obj = new ABC(); System.out.println(obj.num); System.out.println(obj.square(10)); } }Output: 3. Protected Access ModifierProtected data member and method are only accessible by the classes of the same package and the subclasses present in any package. You can also say that the protected access modifier is similar to default access modifier with one exception that it has visibility in sub classes. Protected access modifier example in JavaIn this example the class Test which is present in another package is able to call the addTwoNumbers() method, which is declared protected. This is because the Test class extends class Addition and the protected modifier allows the access of protected members in subclasses (in any packages). Test.java package xyzpackage; import abcpackage.*; class Test extends Addition{ public static void main(String args[]){ Test obj = new Test(); System.out.println(obj.addTwoNumbers(11, 22)); } }Output: 334. Public access modifierThe members, methods and classes that are declared public can be accessed from anywhere. This modifier doesn’t put any restriction on the access. public access modifier example in javaLets take the same example that we have seen above but this time the method addTwoNumbers() has public modifier and class Test is able to access this method without even extending the Addition class. This is because public modifier has visibility everywhere. Test.java package xyzpackage; import abcpackage.*; class Test{ public static void main(String args[]){ Addition obj = new Addition(); System.out.println(obj.addTwoNumbers(100, 1)); } }Output: 101Lets see the scope of these access modifiers in tabular form: The scope of access modifiers in tabular form------------+-------+---------+--------------+--------------+-------- | Class | Package | Subclass | Subclass |Outside| | | |(same package)|(diff package)|Class | ————————————+———————+—————————+——————————----+—————————----—+———————— public | Yes | Yes | Yes | Yes | Yes | ————————————+———————+—————————+—————————----—+—————————----—+———————— protected | Yes | Yes | Yes | Yes | No | ————————————+———————+—————————+————————----——+————————----——+———————— default | Yes | Yes | Yes | No | No | ————————————+———————+—————————+————————----——+————————----——+———————— private | Yes | No | No | No | No | ------------+-------+---------+--------------+--------------+--------Which access specifier is by default in class data?#4) Default Access Modifier. Which access specifier is by default in class data member and member function private/public protected private and public in Python?The members of a class that are declared public are easily accessible from any part of the program. All data members and member functions of a class are public by default.
Is default access specifier private?The default specifier depends upon context. For classes, and interface declarations, the default is package private. This falls between protected and private, allowing only classes in the same package access. (protected is like this, but also allowing access to subclasses outside of the package.)
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