"Loading data for Android 5.0" has encountered a problem. - Parsing Data for android-21 failed

[Problem]

"Loading data for Android 5.0" has encountered a problem.

Parsing Data for android-21 failed
unsupported major.minor version 51.0

[Solution]

1. Change the environmental path to point 1.7/1.8
2. Open Eclipse and goto windows tab-> preference
3. Goto Java->complier and set Compiler compliance level to 1.7 and press apply.
4. Then Goto Installed JRE Section. check if the installed jdk is listed and selected in the list. If not listed give the manual path using search. then select the jdk version and remove other versions in the list.
5. in installed JRE go to execution environment and select the intended java se version and check it in compatible section
6. Presss ok and restart Eclipse.

Try installing JDK 1.8 and reload Eclipse.

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html