Posted in: 10 Tricky Java Interview Questions,Core Java,J2EE Design Patterns
Access Modifiers :
An access modifier is a Java keyword that indicates how a field or method can be accessed. Variables and methods in Java have access restrictions, described by the following access modifiers:
private:
- Used for most instance variables
- private variables and methods are accessible only to methods of the class in which they are declared
- Declaring instance variables private is known as data hiding
- Example: private int x;
default (this means no modifier is used):
- Access is limited to the package in which the member is declared
- Example: int x;
protected:
- Access is limited to the package in which the member is declared, as well as all subclasses of its class
- Example: protected void setName() { . . . }
public:
- The member is accessible to all classes in all packages.
- Declaring public methods is know as defining the class’ public interface.
- Example: public String getName() { . . . }
Java Access Specifiers :
- Access specifiers indicates which mebmers of a class can be used by other classes
- We use of public, protected and private for access specifications
- Packeg access is used when there is no access specifier
- Package access means that all classes in the same package can access the member
- But for all other classes the member is private
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