"SQLException: ORA-06550" when calling PL/SQL function from Java

Question

I want to use Java to retrieve data from database and display it, so I created this PL/SQL function, which returns a cursor:

create or replace function std_getInfoFunc return types.cursortype 
as 
    my_cursor    types.cursorType; 
begin 
    open my_cursor FOR
    SELECT s.FirstName, s.LastName, s.Address, s.City, s.Province
        , s.PostalCode, c.CourseName
    FROM Students s, Courses c, StudentAndCourses cs
    Where s.StudentID = cs.StudentID
        AND c.CourseID = cs.CourseID;
    Return my_cursor;
end; 

In my Java code, I call the function as follows:

try{
    CallableStatement cst=connection.prepareCall("{? = call std_getInfoFunc}");
    cst.registerOutParameter(1, oracle.jdbc.OracleTypes.CURSOR);
    cst.execute();

    res=(ResultSet) cst.getObject(1);

    while(res.next()){
        System.out.println(res.getString(1));
    }
}
catch(SQLException e){
    e.printStackTrace();
}
finally{
    res.close();
    cst.close();
    conn.close();
}

The code produces the following exception:

 run:
  java.sql.SQLException: ORA-06550: line 1, column 13:
   PLS-00905: object SAS.STD_GETINFOFUNC is invalid
  ORA-06550: line 1, column 7:
  PL/SQL: Statement ignored

at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:439)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:395)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:802)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:436)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:186)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:521)
at oracle.jdbc.driver.T4CCallableStatement.doOall8(T4CCallableStatement.java:202)
at        
  oracle.jdbc.driver.T4CCallableStatement.executeForRows(T4CCallableStatement.java:1005)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1307)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3449)
at oracle.jdbc.driver.OraclePreparedStatement.execute(OraclePreparedStatement.java:3550)
at oracle.jdbc.driver.OracleCallableStatement.execute(OracleCallableStatement.java:4710)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.execute(OraclePreparedStatementWrapper.java:1374)
at DBControler.viewStdInfo(DBControler.java:95)
at Test_02.main(Test_02.java:18)

Why?

Solution

Possible causes of error are : (in the snippet - function)

1. The package "types" doesn't exists.

  create or replace package types 
    as 
        type cursorType is ref cursor; 
    end; 
    /

2 Invalid SQL select statement (Table or column has been dropped or altered after creating the function).

You need to write a new function with simple sql statement and run it at Sql prompt and with Java code.