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):

publicclass className {// ...}privateboolean myFlag;staticfinaldouble weeks =9.5;protectedstaticfinalint BOXWIDTH =42;publicstaticvoid 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.