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:
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:
- Visible to the package. the default. No modifiers are needed.
- Visible to the class only (private).
- Visible to the world (public).
- 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.
Java 