about Java

DISCUSSION QUESTIONS: 1. Define encapsulation. 3. Explain why method arguments should be validated before they are used in a method. 4. Why are private data members in a class more secure than public data members? 5. Why are private data members in a class more secure than package-private data members (fields without an access modifier)? 6. From a security viewpoint, why should you not routinely create an accessor for each instance variable? 7. From a security viewpoint, why should you not routinely create a mutator for each instance variable?