The wrapper class for the primitive type int in Java is Integer. It is a final class in the java.lang package that represents an integer value as an object rather than as a primitive value.
Wrapper classes exist because many Java APIs work with objects. For example, generic collections such as ArrayList<Integer> store Integer objects, not raw int values. Java 5 introduced autoboxing and unboxing, allowing the compiler to convert automatically between int and Integer in many contexts: an int can become an Integer, and an Integer can be extracted back to an int.
Integer is more than a container. It provides useful constants and methods, including MIN_VALUE, MAX_VALUE, parseInt, compare, and toString. Integer objects are immutable, meaning their represented value cannot be changed after creation.
A frequent mistake is choosing Number. Number is an abstract superclass for numeric wrappers such as Integer, Long, Float, and Double; it is not the specific wrapper for int. Int is also not Java’s wrapper-class name, and IntWrapper is not a standard Java class.