What is the use of Observable class?
A. It is used to create global subclasses
B. It is used to create classes that other part of the program can observe
C. It is used to create classes that can be accessed by other parts of program
D. It is used to create methods that can be accessed by other parts of program
Answer: Option B
This Question Belongs to Java Program >> Interfaces And Abstract Classes
A. A contract specifying a set of methods that a class must implement
B. A class that cannot be instantiated
C. A class that contains only static methods
D. A subclass of the Object class
In Java, can a class implement multiple interfaces?
A. Interfaces cannot be implemented by classes
B. Only abstract classes can implement interfaces
C. No, a class can only implement one interface
D. Yes, a class can implement multiple interfaces
What is the purpose of an abstract class in Java?
A. To declare abstract methods
B. To provide a base class with common methods and fields
C. To make a class final
D. To declare abstract methods
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