JAVA unit 4

Which class is used to read input from the console in Java?

• • A) FileReader

• • B) BufferedReader

• • C) PrintWriter

• • D) Scanner

Which method is used to write data to a file in Java?

• • A) writeFile()

• • B) print()

• • C) write()

• • D) println()

What is the purpose of bounded types in generics?

• • A) To allow any type as a parameter.

• • B) To restrict the types that can be used as type arguments.

• • C) To enhance performance.

• • D) To simplify code.

Which keyword is used to define an upper bound for a generic type in Java?

• • A) super

• • B) extends

• • C) implements

• • D) restricts

What does the StringBuffer class provide that the String class does not?

• • A) Immutability

• • B) Thread safety

• • C) Mutable strings

• • D) None of the above

Which of the following is a valid declaration of a generic class in Java?

• • A) class MyClass<T> {}

• • B) class MyClass<T extends Number> {}

• • C) class MyClass<T extends Comparable<T>> {}

• • D) All of the above

What will happen if you try to use a non-bounded type as a generic argument in a bounded generic class?

• • A) It will compile successfully.

• • B) It will throw a runtime exception.

• • C) It will cause a compile-time error.

Which method of the String class is used to find the length of a string?

• • A) size()

• • B) length()

• • C) getLength()

• • D) count()

What is the output of new StringBuffer("Hello").append(" World").toString();?

• • A) Hello World

• • B) HelloWorld

• • C) Hello World!

• • D) Hello, World

In which scenario would you use a generic method?

• • A) When you want to create a method that can operate on different types.

• • B) When you need to enforce type safety.

• • C) When you want to reduce code duplication.

• • D) All of the above