A former member of my team used some java code of his own in one of our company's projects. The code comes in the form of JAR libraries and it is currently running in production.
When the guy left, he took the code with him, saying that it didn't belong to the company because it had been developed before coming to work for us.
Does he has the right to do this?
Technically, yes. In the absence of other agreements (like a work-for-hire IP assignment), copyright for code rests with the person who wrote it. If he wrote it before he started working for you (and wasn't working for anyone else at the time), he owns it.<p>Most companies I know are pretty strict about making sure they get licenses for <i>any</i> third-party code that goes into their system, including that written by employees. (I remember once, while working at Google, getting a request from a fellow Googler to "please add a LICENSE file to the PyJSDoc GitHub repository", because they wanted to use it for a project but couldn't without an explicit license, even though I was now working for the same company.) I've seen a few that also include blanket releases into their IP assignment docs, with wording along the lines of "You represent that you have the legal right to use any code that you incorporate into your employer's systems, and grant employer a perpetual royalty-free blahblahblah license to use any such code you authored that has been so incorporated."
From my limited understanding in my jurisdiction (in the US) he probably does indeed own the copyright to the code in question.<p>I have no knowledge of what sort of implied licenses may have been generated, but I would feel comfortable (aside from technical risk) continuing to run those JARs in production for the short term.<p>As a bit of unsolicited advice, have you asked him how much he is willing to sell a license to the code for? Depending on the price, it may be a good win/win solution for you.