Problem
class cannot be resolved to a type error upon compilation. Such errors are mostly due to build path errors - .classpath issues or missing jar or jre.
Resolution
Trial 1 - Perform the clean build.
Trial 2 - Make sure the correct JRE has been selected.
Trial 4 - Make sure that required jar files have been included.
Trial 3 - Make sure that .classpath file is correct and have all required jar references.