title: why `java.lang.SecurityException: Prohibited package name: java` is required?
body: <p>I created a class "String" and placed that in package "java" [ actually i wanted to create <em>java.lang</em> to see which class is loaded by classLoader as </p>
  
  <blockquote>
    <p>Once a class is loaded into a JVM, the
    same class (I repeat, the same  class)
    will not be loaded again  </p>
  </blockquote>
  
  <p>quoted from oreilly ] . But that thing later, why on running this class i am getting<br>
  java.lang.SecurityException: Prohibited package name: <strong>java</strong>  </p>
  
  <p>For which security reason java is not allowing me to have a class in <strong>java</strong> package? What one could do if there will not be no such check?</p>