title: Do threads really do things in Parallel?
body: <p>I need to know some thing about threads. I was writing an small crawler in Java and I will be starting with an URL, add the outgoing URLs to a database and crawl the next one (not multithreaded). </p>
  
  <p>My project will eventually have to be multithreaded. </p>
  
  <p>I have some doubts. When using threads we use a lock on a function so that only one thread should use that function. Is multithreading still useful then?</p>