I'm trying to register a UDF to parse my log file format. Where can I find
documentation for creating and registering a UDF?

My attempts failed with this error:

hive> create temporary function process_line as 'LogProcessor';
FAILED: Unknown exception : Registering UDF Class class LogProcessor which
does not extends class org.apache.hadoop.hive.ql.exec.UDF

Specific questions:

1. Do I need to define the a particular function in the class? For example,
2. What arguments should that function accept?
3. What should be the return type of that function?
4. What if the function needs to return multiple values? Each value mapping
to a column in the table?

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