WRAPPER CLASS

What is a Type Wrapper or simply a Wrapper in Java?

• A) A Wrapper class is an object version of Primitive Data Type
• B) A Wrapper provides additional methods for ease of use
• C) Wrapper types are useful for using with generic collections
• D) All the above

Which primitive data types have wrapper classes available?

• A) byte, short, int, long
• B) float, double
• C) boolean, char
• D) All the above

Choose the correct mapping of Primitive Data Types and Wrapper Classes below?

• A) boolean = Boolean, char = Character
• B) byte = Byte, short = Short, int = Integer, long = Long
• C) float = Float, double = Double
• D) All the above

State TRUE or FALSE. Java primitive data types work faster compared to their Wrapper counter parts.

• A) TRUE
• B) FALSE

Which is the correct way of converting an int value to Integer in below Java code?

• A) Integer in = new Integer(9);
• B) Integer in = Integer.valueOf(9);
• C) Integer in = new Integer("9");
• D) None of the above

Are the sizes of float and Float same or different in Java?

• A) Same
• B) Different

Choose a correct statement about Autoboxing in Java?

• A) Boxing is the process of converting a primitive data to its equivalent Wrapper class type
• B) Unboxing is the process of converting a Wrapper class object to its equivalent primitive data type
• C) Autoboxing is the process of converting Primitive data type to Wrapper Object type automatically. Auto-Unboxing is the process of converting Wrapper type object to Primitive type automatically.
• D) All the above

Which does autoboxing or unboxing in Java?

• A) Compiler
• B) Runtime
• C) Third party tools
• D) None

Autoboxing or unboxing involves replacement of Wrapper objects with Primitives and vice versa. State TRUE or FALSE.

• A) TRUE
• B) FALSE

What is the need for Autoboxing and Unboxing in Java?

• A) Reduces code to be written by developers to convert from Wrapper to Primitive vice versa
• B) Compile time is reduced due to fixed methods followed to automatically convert Objects and Primitives
• C) Auto-unboxing improves memory efficiency by converting Wrapper to Primitive and process when object version is not needed
• D) All the above