The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path

This error typically occurs when you are trying to use the HttpServlet class in a Java project, but the necessary libraries are not included in the project's classpath. To fix this error, you need to add the servlet-api.jar library to your project's classpath.

If you are using Eclipse, you can do this by following these steps:

  1. Right-click on your project in the Package Explorer and select "Properties".
  2. In the Properties window, go to the "Java Build Path" section and click on the "Libraries" tab.
  3. Click on the "Add External JARs" button.
  4. Navigate to the location where the servlet-api.jar library is stored and select it.
  5. Click "Open" to add the library to your project's classpath.

If you are using a different IDE or building your project from the command line, you will need to follow a similar process to add the servlet-api.jar library to your project's classpath.

Note that the servlet-api.jar library is typically included with a Java web application server, such as Apache Tomcat or Jetty. If you are running your application on a web server, you should not include the servlet-api.jar library in your project, as it is already provided by the server. Instead, you should add the server's library path to your project's classpath.