title: difference between keyword and literal in java
body: <p>I am new to java and was reading a book and came across these lines:</p>
  
  <p>"The literals <code>true</code>,<code>false</code>and <code>null</code> are lowercase,not uppercase as in C++ language.Strictly speaking,these are not keywords but literals."</p>
  
  <p>why these are literals, and what requirements are needed for some keywords to be called literal..?</p>