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 servlet libraries are not included in the project's classpath. The recommended fix is to add the servlet API dependency using a build tool like Maven or Gradle.

Maven Add the following to your pom.xml:

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
    <scope>provided</scope>
</dependency>

Gradle Add the following to your build.gradle:

implementation 'javax.servlet:javax.servlet-api:4.0.1'

If you are using Eclipse, you can also fix this by verifying your project settings:

1. Right-click on your project in the Package Explorer and select "Properties".
2. Go to "Java Build Path" > "Libraries" and ensure the correct JRE System Library is selected (preferably a JDK, not a JRE).
3. If adding the library manually, click "Add External JARs", navigate to your server's lib folder (e.g., Apache Tomcat), and select servlet-api.jar.
4. Click "Apply and Close".

For other IDEs or command-line builds, configure your build tool or project settings to include the servlet API dependency.

Note that the servlet API is typically provided by a Java web application server, such as Apache Tomcat or Jetty. When using a build tool, set the dependency scope to provided so it is available during compilation but not packaged with your application. This prevents runtime LinkageError conflicts caused by duplicate classes.