title: Breakpoint in java runtime libraries (rt.jar)
body: <p>Can we not put a breakpoint in the classes in rt.jar?</p>
  
  <p>I am debugging something and I need to put a breakpoint in java.sql.DriverManager, but as soon as I put a breakpoint at some place, eclipse prompts me with the message</p>
  
  <pre><code>Unable to install breakpoint in java.sql.DriverManager due to missing line number attributes. Modify compiler options to generate line number attributes
  </code></pre>
  
  <p>Does this mean that java runtime classes were not compiled for debugging? If yes, then why would such a thing be done. Please help!</p>
  
  <p>Edit1: I am doing remote debugging, the actual web application is running in tomcat on a linux machine, I am on a windows machine. Which rt.jar is the culprit here, the one on my machine or the one on remote machine? And is it possible that rt.jar is not compiled with line numbers and other useful info?</p>
  
  <p>Edit2: The answers to this question has the details <a href="https://stackoverflow.com/questions/271521/locally-declared-variables-can-not-be-inspected">Locally declared variables can not be inspected</a>
  Anyone knows why this is compiled without debugging symbols? How does it affect the performance to keep some metadata or is it something else? </p>