Because CS3 only has JDK 1.6, if you deploy Java classes compiled for 1.7 VM, the server won't be able to run them.

In Eclipse, right click on your project and select Properties -> Java Compiler. and make sure Compiler Compliance Level, Generated .class File Compatibility, and Source Compatibility all say 1.6. If not, check Enable Project Specific Settings and change them to 1.6.

If you use Maven, include the following in your pom.xml:

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>2.3.2</version>
        <configuration>
          <source>1.6</source>
          <target>1.6</target>
        </configuration>
      </plugin>

Note that this problem only affects HW2. In future assignments you'll only need to turn in source code.

I made a completely separate workspace on my computer with a separate copy of eclipse to run the program with jre6. Now I have both a 6 & a 7 working perfectly locally on my machine, but it still won't run on cs3 even after I completely switched out the copies of all my class and jsp files and uploaded the xml file created by the new project. It should be at http://cs3.calstatela.edu:8080/cs520stu14/Main

but still nothing. What am I supposed to do?