What are Wrapper classes and what are they used for ?

Question

What are Wrappter classes and what are they used for ?..Also, any examples would be great to understand this concept

Answer 1

Wrapper classes are used to enclose primitive data
types so that they can be used in instances where an
object is required. For example, if you want to add an
integer to an ArrayList, you can't use this:java.util.List al = new ArrayList();
int i=123;
al.add(i);because the ArrayList expects data of type object. In
order to all the integer to the ArrayList, you must wrap
it in the Integer wrapper class. This works:java.util.List al = new ArrayList();
int i=123;
al.add(new Integer(i));Hope that helps.
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