abandoned connections

[Rob Sargent]

I think I have all my calls for new connections in try/with blocks, but 
things went bump in the night at AWS/RDS yesterday and I'm wondering if 
I missed one or if the try/with isn't as safe as I thought.

   00:10:12.201 [https-jsse-nio-10.0.2.28-15002-exec-11] INFO
   edu.utah.camplab.jx.PayloadFromMux -
   bulk."rjs_GEV15_20_074d449b_c3ba_499f_83e3_f48427fe0156": Begin
   transfer from bulk to segment
   26-May-2021 00:10:55.092 WARNING [Tomcat JDBC Pool
   Cleaner[1731185718:1621976215058]]
   org.apache.tomcat.jdbc.pool.ConnectionPool.abandon Connection has
   been abandoned PooledConnection[org.postgresql.jdbc.PgConnection@2e\
   cd1168]:java.lang.Exception
            at
   
org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1163)
            at
   
org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:816)
            at
   
org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:660)
            at
   
org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:198)
            at
   
org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:132)
            at
   
org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:90)
            at
   
edu.utah.camplab.servlet.AbstractSGSServlet.getDbConn(AbstractSGSServlet.java:123)
            at
   
edu.utah.camplab.servlet.AbstractSGSServlet.getDbConn(AbstractSGSServlet.java:105)
            at
   
edu.utah.camplab.servlet.PayloadSaveServlet.doPost(PayloadSaveServlet.java:50)
            at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
            at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
in my tomcat log.  I see *nothing* that matches this in the AWS/RDS log 
views.

And here's the getDbConn call in the doPost method (though I see it has 
a superfluous close() call):

      protected void doPost(HttpServletRequest req, HttpServletResponse
   resp) {
        //HashMap<String, ArrayList<String>> pmap = getParameterMap(req);
        logger.error("payload save called");
        try (Connection copyConn = getDbConn(req, resp)) {
        ObjectMapper jsonMapper = JsonMapper.builder().addModule(new
   JavaTimeModule()).build();
        jsonMapper.setSerializationInclusion(Include.NON_NULL);

            AbstractPayload payload =
   jsonMapper.readValue(req.getInputStream(), AbstractPayload.class);
            logger.error("received payload");
            String redoUrl =
   String.format("jdbc:postgresql://%s:%d/%s", getDbHost(),
   getDbPort(), getDbName(req));
            payload.setConnection(copyConn);
            payload.setDbUrl(redoUrl);
            payload.write();
            logger.error("finished db write");
            resp.setContentType("plain/text");
            resp.setStatus(200);
            resp.getOutputStream().write("SGS_OK".getBytes());
            resp.getOutputStream().flush();
            resp.getOutputStream().close();
            copyConn.close();
          }
        catch
   (com.fasterxml.jackson.databind.exc.MismatchedInputException mie) {
          logger.error("transform failed: " + mie.getMessage());
          resp.setContentType("plain/text");
          resp.setStatus(461);
          sendBadNews(resp, mie, "json formatting issue, perhaps");
        }
        catch (IOException | SQLException ioe) {
          resp.setStatus(460);
          sendBadNews(resp, ioe, "database trouble, likely");
        }
      }