The EXTERNAL statement specifies the name and classpath of external methods used by the routine. Note that the Java method must be a public static method in the public class. To specify an EXTERNAL statement, use the following syntax: 

EXTERNAL <method_name> CLASSPATH: <classpath>

where

method_name
is the name of a method external to the function or procedure to be called by the routine.
classpath
is the name of the classpath for your external method.