为什么jdbc连接oracle不成功（请看程序和编译。。）？？

// Application1.java *****程序*****

import java.sql.*;
import oracle.jdbc.*;

public class Application1
{
public static void main (String args []) throws SQLException, ClassNotFoundException
{
// Load the Oracle JDBC driver
Class.forName ("oracle.jdbc.driver.OracleDriver");

String URL="jdbc:oracle:thin:@130.130.0.228:1521:ora";
try {
Connection conn = DriverManager.getConnection (URL,"scott","tiger");
conn.setAutoCommit(true);
// Create a Statement
Statement stmt = conn.createStatement ();

// Select the ENAME column from the EMP table
ResultSet rset = stmt.executeQuery ("select ENAME from EMP");

// Iterate through the result and print the employee names
while (rset.next ())
System.out.println (rset.getString (1));
} catch(SQLException ex) {
System.err.println("-----SQLException-----");
System.err.println("SQLState: " + ex.getSQLState());
System.err.println("Message: " + ex.getMessage());
System.err.println("Vendor: " + ex.getErrorCode());
ex.printStackTrace();
}
}
}

//***** 编译执行结果 ****
D:\JBuilder4\jdk1.3\bin\javaw -classpath "E:\kong\test1\classes;D:\JBuilder4\jdk1.3\demo\jfc\Java2D\Java2Demo.jar;D:\JBuilder4\jdk1.3\jre\lib\i18n.jar;D:\JBuilder4\jdk1.3\jre\lib\jaws.jar;D:\JBuilder4\jdk1.3\jre\lib\rt.jar;D:\JBuilder4\jdk1.3\jre\lib\sunrsasign.jar;D:\JBuilder4\jdk1.3\lib\dt.jar;D:\JBuilder4\jdk1.3\lib\tools.jar;F:\orant\jdbc\lib\classes102.zip;F:\orant\jdbc\lib\classes111.zip" test1.Application1
-----SQLException-----

SQLState: null

Message: Refused:ROR=(CODE=12505)(EMFI=4))))

（请各位指教，谢谢）