Java UDFs can only run in EXECUTE PROTECTED mode.
For Java UDFs, the COMPILE option operates identically to UDFs written in C or C++ with the exception that the extension the JAR file references in the Java UDF EXTERNAL NAME clause is redistributed to all affected nodes on the system. Redistribution is useful when a JAR file is missing on a given node. Note that you cannot specify the COMPILE ONLY option for Java UDFs.
The ONLY clause on the COMPILE option for UDFs written in Java generates preamble files, but does not redistribute their associated JAR file.
For more information, see CREATE FUNCTION and REPLACE FUNCTION (External Form) and Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.