Understanding Wrapper Classes in JAVA

Study Notes

Wrapper Classes

Wrapper classes are object representations of the eight primitive types in Java.
Specific wrapper classes include: Boolean, Byte, Short, Integer, Long, Float, Double, and Character.

Purpose of Wrapper Classes

Wrapper classes provide useful methods for operations that primitive types lack.
They enable functionalities such as conversion and manipulation of primitive data.

java.util Package

The java.util package contains both wrapper classes and various collection classes.
It serves as a container for utility classes, enhancing functionality in Java.

Auto-boxing and Unboxing

Auto-boxing refers to the automatic conversion of a primitive type to its corresponding wrapper class.
Unboxing is the reverse process, where a wrapper class is converted back to its primitive type.

Casting in Java

Casting is the assignment of one primitive data type's value to another.
Two types of casting exist:
- Implicit Casting: Automatic conversion from a smaller type to a larger type.
- Explicit Casting: Manual conversion from a larger type to a smaller type.
boolean cannot be cast to any other primitive type.

Widening Casting (Up-Casting)

Widening casting automatically converts smaller data types to larger ones.
The flow of widening casting is: byte → short → char → int → long → float → double.

Narrowing Casting (Down-Casting)

Narrowing casting requires manual conversion from a larger type to a smaller type.
The flow of narrowing casting is: double → float → long → int → char → short → byte.

Data Types in Java

Java features two main categories of data types:
- Primitive Data Types: Basic types that store simple values.
- Reference Types (Non-Primitives): Allows method calls and operations, with String as an example.

Primitive Data Types

Java has eight primitive data types:
- Numeric: byte, short, int, long
- Floating Point: float, double (both types store decimal values)
- Character: char (stores single characters)
- Boolean: boolean (stores true or false values)

Description

This quiz explores the concept of Wrapper classes in JAVA, providing insight into their function and importance in programming. Discover the relationship between primitive data types and their corresponding wrapper classes through a series of flashcards.