What are the access modifiers in java (e.g., private, protected, public)?

When answering this question, it’s important to succinctly describe the various access modifiers in java and their usage. Discuss how public modifier makes a member accessible from any other class, private restricts it to the class it is defined in, and protected allows access within the same package and subclasses. Mentioning default (or package-private) where no modifier is used, and it allows access only within the same package, could also add to your response. Relate the theoretical knowledge back to practical application and how using the appropriate access modifier is essential in designing robust and secure java applications, especially in a financial context like at fidelity investments.