title: why are we adding server runtime library in java build path in eclipse?
body: <p>I have created one sample jsp file using eclipse. Then eclipse is showing one error "The superclass javax.servlet.http.HttpServlet was not found  ". </p>
  
  <p>According to <a href="https://stackoverflow.com/questions/26936848/the-superclass-javax-servlet-http-httpservlet-was-not-found-on-the-java-build">The superclass &quot;javax.servlet.http.HttpServlet&quot; was not found on the Java Build Path</a> , I have done the following .
  Project Properties-> Java Build Path-> Add Library -> Select "Server Runtime" from the list-> Next->Select "Apache Tomcat"-> Finish</p>
  
  <p>and it worked fine. But I don't understand the use of this procedure. Please tell me why we are adding server runtime library to java build path.</p>