Introduction to Java modifiers

Java modifiers are split into two categories :

• Access modifiers;
• Non-access modifiers.

Access modifiers are the “responsible” for determining the accessibility of a class, an interface and their methods and variables. In Java there are three access modifiers :

• public;
• protected;
• private.

and, four access levels :

• public;
• protected;
• private;
• default.

Non-access modifiers are used to assign special privileges, responsibilities, and behavior to the Java types and entities. Non-access modifiers which can be used to characterize the java classes, interfaces, methods and variables  are :

• abstract;
• final;
• static;
• synchronized;
• native;
• strictfp;
• transient;
• volatile.

The Java Certification OCA 7 Programmer I requires to know only three of the non-access modifiers : abstract, final and static.