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

This error typically occurs when a required library or dependency is missing from your project's build path. To resolve this issue, you can try the following steps:

1. Check if the required library (in this case, javax.servlet.http.HttpServlet) is present in your project's build path. If not, add it to your project's build path.

2. Ensure that the library is located in the correct directory and that the directory is included in the CLASSPATH environment variable.

3. Refresh your project's build path by right-clicking on the project and selecting "Refresh" or by pressing F5.

4. If you're using an IDE like Eclipse or IntelliJ, try cleaning and rebuilding your project.

If none of these steps work, you may need to investigate further to determine the root cause of the issue.