Executing Java Programs in Oracle Database

With this blog post I am trying to give a overview of a very powerful feature of Oracle, but mostly not used or unknown to developers. Oracle Database can store a Java Byte Code and run Java stored procedures in the same way as PL/SQL stored procedures.

I am picking a very simple java code, which takes 2 integer arguments and returns sum of them in integer.

1) Create a file "math_java.java" as follows

public class math_java 
{
    public static int sum_java(int a, int b)
    {
        int sum;
        sum = a+b;
        return sum;
    }
}

2) Compile the "math_java.java" file using Java compiler to generate class file

javac math_java.java

3) Load "math_java.class" on database server using loadjava

loadjava -user scott math_java.class

4) Now we need to publish above JAVA class in database by create a mapping function

CREATE or replace FUNCTION sum_java(a number, b number) RETURN number AS LANGUAGE JAVA NAME 'math_java.sum_java(java.lang.int, java.lang.int) return java.lang.int';

All done :) Now we can use this Java Stored Procedure anywhere in our Oracle Database. Lets give a try.

SQL> select sum_java(5,7) from dual;
       SUM
----------
        12

Now one can ask what is the benefit of storing a JAVA code in Oracle Database. I personally saw following main benefits
- Power of JAVA in your hand
- Performance is very high
- Easy to use


Please look into Oracle Documentation it you want to read more about it.

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