Hive:Execution Error, return code -101 from org.apache.hadoop.hive.ql.exec.FunctionTask Ask

I wrote a test.sql file and ran it with hive. I got the error when hive was parsing to the code(show below):

[CODE]:
CREATE TEMPORARY FUNCTION foo AS "com.mytest.udaf.HelloWorldFoo";

[ERROR]:
This query failes with the error: "Execution Error, return code -101 from
org.apache.hadoop.hive.ql.exec.FunctionTask"

PS: Hadoop was running on Java 6.

the problem was that the UDAF class was compiled with Java 7 and Hadoop was running on Java 6.