Understanding ps -ef "command" column

When I do a ps -ef, in the command column, I see:

postgres: postgres dbname 10.170.1.60(57413) idle

I get all of this, except the "57413".  What does this mean, and more importantly, how can I tie that number back to a connection that I've acquired via JDBC?

In my case, I've got a connection that's hanging around after my code should have closed it, which means almost certainly that I've got problems in my code, but I'd love to be able to get that "57413" number from my jdbc object and write it to my logs to troubleshoot this.  Any ideas?

Thanks,
Dave