Unsupported major.minor version 51.0

java.lang.UnsupportedClassVersionError: javax/annotation/ManagedBean : Unsupported major.minor version 51.0

it occured when tomcat version and java version are not matched.
For my case, it occured when I used tomcat-embed-core-8.0.28.jar and java 1.6 version.
I solved this problem by changing the java version to 1.7.