# Wrapper Classes Part 02

## Introduction

1. With the help of wrapper classes, we can wrap primitives to objects so that we can handle primitives just like objects.
    
    1. Constructor Summary
        
        1. Int- Integer(integer,string)
            
        2. byte- Byte(byte,string)
            
        3. Char- Character(character)
            
        4. boolean- Boolean(boolean,string)
            
        5. Double - Double(double,string)
            
        6. Float-Float(float,string)
            
        7. short-Short(short,string)
            
    2. In all wrapper classes tostring() method overrides to return the content
        
    3. The equals method is overridden in all wrapper classes to compare the content
        
    
    ## The usage of wrapper classes
    
    1. Utility methods: Helper method/static methods
        
        1. valueof(): it is used wrapper object for the given primitive or string
            
            * we can create wrapper classes as
                
                ```java
                class HelloWorld {
                    public static void main(String[] args) {
                       Integer i1 = new Integer(10);
                    }
                }
                // this method of creating wrapper classes has been deprecated hence we have one more alternative of creating wrapper classes
                                                                             
                
                
                
                
                class HelloWorld {
                    public static void main(String[] args) {
                       Integer i1= Integer.valueOf(10);// this is the use of value of to create new wrapper classes 
                       System.out.println(i1);
                    }
                }
                             
                ```
                
        2. XXXXvalue()
            
            * Used to convert objects to primitive
                
                ```java
                
                class HelloWorld {
                    public static void main(String[] args) {
                       Integer i1= Integer.valueOf(10);
                       System.out.println(i1.intValue());
                       System.out.println(i1.floatValue());
                       System.out.println(i1.byteValue());
                       System.out.println(i1.shortValue());
                       System.out.println(i1.longValue());
                    }
                }
                ```
                
        3. parseXXX()
            
            * used to convert string to primitive
                
        4. toString()
            
            * A `toString()` is an in-built method in Java that returns the value given to it in *string* format. Hence, any object that this method is applied on, will then be returned as a *string object*.
                
    
    ## Autoboxing & Unboxing
    
    1. *Autoboxing* is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes. For example, converting an int to an Integer, a double to a Double, and so on.
        
    2. If the conversion goes the other way, this is called *unboxing*.