Mysterious Eclipse JSP Validation Errors

Well, I found how to solve this error. Add this to your Maven dependency(pom.xml):

<!-- dependency to fix JSPServletException -->
    <dependency>
        <groupId>org.apache.tomcat</groupId>
        <artifactId>jsp-api</artifactId>
        <version>6.0.32</version>
        <scope>provided</scope>               
    </dependency>

Do comment if you find it useful, as much as it helped me.

Based on the comments, I ended up turning off part of the JSP validation, which fixed this.

1. Go to "Project->Properties->Validation".
2. Click "Configure Workspace Settings...".
3. Unselect options for JSP Syntax Validator (both manual and build).

I was hoping I was missing something and there was a way to fix this, but I have to concede that the JSP validation is junk.

I had the same problem, the problem is the jsp-api library, you can add the dependency to your pom (as explained in other answers) or you can also add the target run-time and eclipse will automatically add that library to your class-path:

Project -> Properties -> Targeted Runtimes 

And select your server.