Visibility (controlling access to members of a class)

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Syntax

  • public type name[ = value];
  • private type name[ = value];
  • protected type name[ = value];
  • type name[ = value];
  • public class name{
  • class name{

Remarks

From the Java tutorial:

Access level modifiers determine whether other classes can use a particular field or invoke a particular method. There are two levels of access control:

  • At the top level—public, or package-private (no explicit modifier).
  • At the member level—public, private, protected, or package-private (no explicit modifier).

A class may be declared with the modifier public, in which case that class is visible to all classes everywhere. If a class has no modifier (the default, also known as package-private), it is visible only within its own package.

At the member level, you can also use the public modifier or no modifier (package-private) just as with top-level classes, and with the same meaning. For members, there are two additional access modifiers: private and protected. 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.

The following table shows the access to members permitted by each modifier.

Access Levels:

ModifierClassPackageSubclassWorld
publicYYYY
protectedYYYN
no modifierYYNN
privateYNNN

Related Examples

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Tuesday, March 7, 2017
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