Access modifier is a reserve keyword or we can say visibility controls which is used to restrict access.We can use these access modifier to determine whether a fields or methods in a class ,can be called or used by another class or sub class or not.That means these access modifiers can prevent unauthorized updation or execution of fields and methods of the particular object.
COMPILED AND INTERPRETED:
In a computer language either compiler or interpreter is used. But in Java both are used .The Java compiler translates source code into bytecode. Bytecodes are not machine codes after compiles the program Java interpreter generates machine codes that can be executed or running the program that is why we can say that Java compiled and interpreted. These two steps provide security.
Java is an object oriented programming language which was developed by James Gosling at Sun Micro System in 1991 and released in 1995.The original name of Java called OAK. Java was designed for the development of electronics devices like TVs, Machines etc.