Cannot resolve symbol 'HttpServletResponse'

The error "Cannot resolve symbol 'HttpServletResponse'" occurs when the Java compiler cannot find the import statement or the class definition for the HttpServletResponse class. This class is part of the Java Servlet API, so it is likely that you have not properly imported the necessary library.

To resolve this issue, make sure you have the following import statement at the top of your Java file:

import javax.servlet.http.HttpServletResponse;

If you have already added this import statement but still encounter the error, it could be due to a missing or incorrect Servlet API library in your project's dependencies. In that case, you need to add the Servlet API library to your project.

If you are using a build tool like Maven or Gradle, you can add the Servlet API dependency in your project's configuration file (pom.xml for Maven or build.gradle for Gradle).

For Maven, add the following dependency to your pom.xml file:

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

For Gradle, add the following dependency to your build.gradle file:

dependencies {
    providedCompile 'javax.servlet:javax.servlet-api:4.0.1'
}

After adding the dependency, rebuild your project to resolve the "Cannot resolve symbol 'HttpServletResponse'" error.