Understanding Call Specs

To publish Java methods, you write call specs. For a given Java method, you declare a function or procedure call spec using the SQL CREATE FUNCTION or CREATE PROCEDURE statement. Inside a PL/SQL package or SQL object type, you use similar declarations.

You publish value-returning Java methods as functions and void Java methods as procedures. The function or procedure body contains the LANGUAGE JAVA clause. This clause records information about the Java method including its full name, its parameter types, and its return type. Mismatches are detected only at run time.

As Figure 3-1 shows, applications call the Java method through its call spec, that is, by referencing the call-spec name. The run-time system looks up the call-spec definition in the Oracle data dictionary, then executes the corresponding Java method.

Figure 3-1 Calling a Java Method

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