To unbox an object : Autobox Unbox « Data Type « Java Tutorial

1. Java Tutorial
2. Data Type
3. Autobox Unbox

Simply assign that object reference to a variable of its corresponding primitive type

public class MainClass {
  public static void main(String args[]) {
    Integer iOb = 100; // autobox an int

    int i = iOb; // auto-unbox

    System.out.println(i + " " + iOb); 
  }
}