clarify my doubt

[karthik. G gopalan]

what is the difference between using int and Integer types in java. and also tel me about the wrapper classes and why they are used.

[Jesper de Jong]

The data type "int" is a primitive type, and "Integer" is a class; it's a wrapper class for "int".

In Java, primitives are not objects. Sometimes that is inconvenient. For example, in collection classes such as ArrayList, Vector etc. you can only store objects. You can't store primitives in those collections. Wrapper classes are used to represent the primitive types as objects, so you can for example store them in a collection.