How are wrapper classes used in data validation?
Wrapper classes can be used to represent nullable values in databases, which can be useful when a field is not required.
How are wrapper classes used in generic data structures?
Generic data structures like `ArrayList<Integer>` require objects, so wrapper classes are used to store primitive data.
What is a wrapper class?
A class that encapsulates a primitive data type, allowing it to be treated as an object.
What is the Integer class?
A wrapper class for the primitive type `int`.
What is the Double class?
A wrapper class for the primitive type `double`.
What is autoboxing?
The automatic conversion of a primitive type to its corresponding wrapper class object.
What is unboxing?
The automatic conversion of a wrapper class object to its corresponding primitive type.
Why use wrapper classes?
To use primitive types in contexts that require objects, such as collections or methods expecting objects.
Can Integer objects be null?
Yes, unlike the primitive `int`, an `Integer` object can be assigned a null value.
What is the purpose of the `intValue()` method?
It returns the `int` value of an `Integer` object.
What is the purpose of the `doubleValue()` method?
It returns the `double` value of a `Double` object.
Why are wrapper classes useful with collections?
Collections like `ArrayList` can only store objects, not primitive types. Wrapper classes allow you to store primitive data in collections.
What is the difference between `int` and `Integer`?
`int` is a primitive type; `Integer` is a class that wraps the `int` type. `Integer` can be null, `int` cannot.
What is the difference between `double` and `Double`?
`double` is a primitive type; `Double` is a class that wraps the `double` type. `Double` can be null, `double` cannot.
