How to write user defined wrapper class in java?
<p>I have a question on wrapper classes. What I know is that it converts primitive datatypes to objects. But what I really want to know is that how is this achieved? What I mean is how do I write my own wrapper class? And also I would like to understand the depth of Java. Is it possible to define my own datatype? write my own collections? Is there any book which will give me real understanding of Java?</p>

<p>If anyone can tell me about this then that would be helpful.</p>
