title: Java String best practices
body: <p>I have 4 String parameter's in Java (from request object)</p>
  
  <pre><code>String dd = req.getParameter(dd);
  String mm = req.getParameter(mm);
  String yyyy = req.getParameter(yyyy);
  </code></pre>
  
  <p>after validating dd,mm,yyyy I am building date
  object in 4th String variable by building<code>String date = dd+"/"+mm+"/"+yyyy;</code> again in some places i need to replace the date 
  format as following,</p>
  
  <pre><code>date = yyyy+mm+dd;
  date =mm+"/"+dd+"/"+yyyy;  // storing in db need this format
  </code></pre>
  
  <p>How much memory would consume since 4 objects need to pass
  till persist in table? Was it costlier memory call? Is there any best practice?
  At last howmany string objects would be in Stringpool?</p>