P1_APLab2Quiz_B3B4

What is the primary purpose of abstract methods in Java?

• To create methods that can only be accessed within the same package.

• To prevent the instantiation of abstract classes.

• To define methods that must be implemented by any concrete class derived from the abstract class.

• To provide default implementations for methods in derived classes.

In Java, if an exception is thrown in a try block and there are multiple catch blocks, what happens if the exception type does not exactly match any catch block but is a subclass of one of the catch block's parameters?

• The compiler throws an error because of ambiguity.

• The catch block with the superclass parameter will be executed.

• The catch block with the subclass parameter will be executed.

• The program will terminate without handling the exception.

Which of the following statements about checked and unchecked exceptions in Java is correct?

• Checked exceptions must be caught or declared in the method signature using throws keyword.

• Unchecked exceptions are always caught by the compiler.

• Checked exceptions are subclasses of RuntimeException.

• Unchecked exceptions must be caught using try-catch blocks.

Which statement is false regarding abstract classes in Java?

• Abstract classes can have abstract methods with or without method bodies.

• Abstract classes can be declared as final to prevent further inheritance.

• Abstract classes cannot be instantiated directly; they need to be subclassed.

• Abstract classes can have constructors for initializing instance variables.

Predict the output.

• A C

• A B C

• B C

• B

What happens if a method uses throws but does not throw any exception?

• It will cause a compilation error.

• It will throw a runtime exception.

• It will throw a checked exception automatically.

• It will not cause any issue.

In Java, why can't methods in interfaces have access modifiers other than public?

• It violates the encapsulation principle.

• Interfaces are always public, so their methods are implicitly public.

• It leads to ambiguity in method visibility.

• Methods in interfaces can have different access modifiers based on the implementing class.

Which of the following situations is best represented by a checked exception in Java?

• The program runs out of memory due to a logic error.

• The program encounters a divide-by-zero operation.

• The program attempts to open a file that does not exist.

• The program enters an infinite loop due to a coding mistake.

Which statement is false regarding interfaces in Java?

• Interfaces can have method declarations without method bodies.

• A class can implement multiple interfaces in Java.

• Interfaces can contain instance variables that can have default values.

• Interfaces can have constructors for initializing instance variables.

Which of the following statements is false regarding exceptions and errors in Java?

• Exceptions are events that occur during the execution of a program that disrupts the normal flow of instructions.

• Errors are typically ignored in Java programs as they are part of the normal execution flow.

• Exceptions can be caught and handled using try-catch blocks.

• Errors are typically not recoverable situations, and programs should not catch errors.