title: What is a validationQuery with respect to databases and JNDI?
body: <p>I seem to be having the same exact problem as the poster of <a href="https://stackoverflow.com/questions/2591420/sql-anywhere-11-jz0c0-connection-is-already-closed">this original SO question</a>.</p>
  
  <p>The problem is, he answered his own question with the following comment:</p>
  
  <blockquote>
    <p>I solved my problem, I added a validationQuery to my JNDI datasource.</p>
  </blockquote>
  
  <p>Unfortunately, that doesn't mean anything to me, and doesn't help me solve my problem. So I ask: what is a "<code>validationQuery</code>" with respect to my database (Sybase) and the JNDI entry used to hold the server lookup info?</p>
  
  <p>Thanks in advance.</p>