Which of the following is true about method declarations in interfaces?

• A. They can have any access modifier
• B. They must be declared public and abstract
• C. They can be static or final
• D. They can contain implementation details

Answer: (B)

When it comes to method declarations in interfaces, it is indeed accurate that they must be declared public and abstract. This is because, by default, all methods in an interface are considered public, meaning they must be accessible to any implementing class. Additionally, methods in an interface are inherently abstract, indicating that they do not provide a body and must be implemented by any class that implements the interface.

This requirement is foundational to the concept of interfaces in Java, promoting a contract-like behavior where an interface outlines what methods a class should implement, without dictating how those methods should perform their functions.

In modern Java (versions 8 and above), interfaces can contain default and static method implementations, but these do not contradict the requirement for method declarations to be public and abstract by default; rather, they add additional capabilities to interfaces. However, traditional method declarations in interfaces remain public and abstract unless explicitly defined otherwise.

Other statements regarding method declarations in interfaces do not hold true in the context described. For example, while methods cannot have other access modifiers such as private or protected in standard interfaces, they are also not allowed to be declared static or final in a manner that steps outside the conventions of interface design. Thus, the adherence to public and abstract in method declaration is