Modifier types

Modifier types

Modifiers are keywords that you add to those definitions to change their meanings. The Java language has a wide variety of modifiers, including the following:

• Java Access Modifiers

• Non Access Modifiers

To use a modifier, you include its keyword in the definition of a class, method, or variable. The modifier precedes the rest of the statement, as in the following examples (Italic ones):

public class className { // ... } private boolean myFlag; static final double weeks = 9.5; protected static final int BOXWIDTH = 42; public static void main(String[] arguments) { // body of method }

Access Control Modifiers:

Java provides a number of access modifiers to set access levels for classes, variables, methods and constructors. The four access levels are:

1. Visible to the package. the default. No modifiers are needed.

2. Visible to the class only (private).

3. Visible to the world (public).

4. Visible to the package and all subclasses (protected).

Non Access Modifiers:

Java provides a number of non-access modifiers to achieve many other functionality.

• The static modifier for creating class methods and variables

• The final modifier for finalizing the implementations of classes, methods, and variables.

• The abstract modifier for creating abstract classes and methods.

• The synchronized and volatile modifiers, which are used for threads.