title: JVM HOT Swapping
body: <p>What is JVM Hot Swapping?</p>
  
  <p>Many definitions say that this feature allows code to updated on the fly during de-bugging.</p>
  
  <p>And a few restrictions such as hot swapping is limited to updating method bodies only, and trying to add methods and fields to classes would not succeed.</p>
  
  <p>Can anyone explain this with code.</p>