Run Java Programs in plsql

Java Class

1. login to db server
2. install java sdk sudo yum install java-1.8.0-openjdk‘
3. check java -v
4. mdkr myJavaFile
5. nano Square_Cube.java
6. javac Square_Cube.java
7. it creates a new file Square_Cube.class
8. loadjava -thin -user db_user/db_pwd@localhost:1521/xepdb1 -resolve -verbose Square_Cube.class
9. this will create a new java class entry in your db

public class Square_Cube{
        public static int Square (int a ) {
                return a*a;
        }
        public static int Cube (int b) {
                return b*b*b;
        }
}

Create Or Replace Function square(a In Number) Return Number As
   Language Java Name 'Square_Cube.Square(int) return int';

Create Or Replace Function Cube(b In Number) Return Number As
   Language Java Name 'Square_Cube.Cube(int) return int';

select square(10) ,cube(10) from dual;

Java Source

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

Create Or Replace Function helloworld Return Varchar2 As
   Language Java Name 'Hello.World () return java.lang.String';
/

Declare
   v_string Varchar2(100 Char);
Begin
   v_string := helloworld();
   
End;
/

Select helloworld
From   dual;