Calling Java from PL/SQL

Can any one please help me on this: I want to call one java program from the Pl/SQL, Oracle RDBMS, the below are the settings

Windows 7 machine, Java is installed on C:\Program Files\Java\jdk1.7.0_02

I created one directory to keep the java files. D:\Java, it has one hello.java file in it.

public class Hello
{
  public static String world()
  {
    return "Hello world";
  }
}

this was compiled fine, and the .class file was generated in the same directory.

Since I have to call this function using PL/SQL, here is the PL/SQL function I've written:

create or replace
FUNCTION helloworld RETURN VARCHAR2 AS
LANGUAGE JAVA NAME 'Hello.world () return java.lang.String';

and this is the PL/SQL procedure:

create or replace
PROCEDURE hellow
AS
  my_string varchar2(400 char);
begin
  my_string:=helloworld();
  dbms_output.put_line('The value of the string is ' || my_string);
end;

both the function and the procedure compiled fine using the SQL/developer.

When I tried running this procedure:

set serveroutput on;
execute hellow;

the following error is coming:

Error starting at line 2 in command: execute hellow Error report: ORA-29540: class Hello does not exist ORA-06512: at "ORACLE_SOURCE.HELLOWORLD", line 1 ORA-06512: at "ORACLE_SOURCE.HELLOW", line 5 ORA-06512: at line 1
29540. 00000 -  "class %s does not exist"  
*Cause:    Java method execution failed to find a class with the indicated name.
*Action:   Correct the name or add the missing Java class.

I placed the .class file in the bin folder also, but still the same error is coming. Can anyone please have a look at this.

You can also compile and save your java source directly in the database, like stored procedures:

CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "Hello" AS
public class Hello
{
  public static String world()
  {
    return "Hello world";
  }
};
/

> Java created

Calling this function is straightforward and doesn't need additional settings:

CREATE OR REPLACE
FUNCTION helloworld RETURN VARCHAR2 AS
LANGUAGE JAVA NAME 'Hello.world () return java.lang.String';
/

DECLARE
   my_string VARCHAR2(400 CHAR);
BEGIN
   my_string := helloworld();
   dbms_output.put_line('The value of the string is ' || my_string);
END;
/

> The value of the string is Hello world

> PL/SQL procedure successfully completed