Wrapper classes in Java
The wrapper class in Java provides the mechanism to convert primitive into object and object into
primitive.
Since J2SE 5.0, autoboxing and unboxing feature convert primitives into objects and objects into
primitives automatically. The automatic conversion of primitive into an object is known as autoboxing and
vice-versa unboxing.
Use of Wrapper classes in Java
Java is an object-oriented programming language, so we need to deal with objects many times like in
Collections, Serialization, Synchronization, etc. Let us see the different scenarios, where we need to use the
wrapper classes.
o Change the value in Method: Java supports only call by value. So, if we pass a primitive value, it
will not change the original value. But, if we convert the primitive value in an object, it will change
the original value.
o Serialization: We need to convert the objects into streams to perform the serialization. If we have a
primitive value, we can convert it in objects through the wrapper classes.
o Synchronization: Java synchronization works with objects in Multithreading.
o java.util package: The java.util package provides the utility classes to deal with objects.
o Collection Framework: Java collection framework works with objects only. All classes of the
collection framework (ArrayList, LinkedList, Vector, HashSet, LinkedHashSet, TreeSet, PriorityQueue,
ArrayDeque, etc.) deal with objects only.
The eight classes of the java.lang package are known as wrapper classes in Java. The list of eight wrapper
classes are given below:
Primitive Type
Wrapper class
boolean
Boolean
char
Character
byte
Byte
short
Short
int
Integer
