Java Database Connectivity (JDBC)

Hello,
I'm an intern and I'm trying to get the number of rows from result set in oracle using rs.last() and rs.beforeFirst() methods but I got an error. Could Below is my sample code:

import java.sql.*;

public class SarueckConnect {

public static void main(String[] args) {

Connection con = null;
Statement stmt = null;
ResultSet re = null;

String[] ParamArray;
ParamArray = new String[24];

//Properties logon;
try {
Class.forName("oracle.jdbc.driver.OracleDriver"); //Loading the Oracle Driver.
con = DriverManager.getConnection
("jdbc:oracle:thin:@258.8.159.215:1521:test_DB","data","data"); //making the connection DB.
stmt = con.createStatement ();// Sending a query string to the database
//stmt.executeUpdate("UPDATE test_table set steuk = 6 WHERE steuk = 5");
ResultSet rs = stmt.executeQuery("SELECT mandt,kokrs,werks,arbpl,aufnr,vornr,ile01,"+
"lsa01,ism01,ile02,lsa02,ism02,ile03,lsa03,ism03,ile04,lsa04,ism04,steuk,matnr,budat,"+
"kostl,pernr,rueckid FROM test_table where steuk =6");

//Print the result out.

rs.last(); //This is the line which give an error.
int rows = rs.getRow();
rs.beforeFirst();// I presume this is wrong to.

ParamArray = new String[24*rows];

int counter=0;

while (rs.next()) {
for (int i = 1; i <= 24; i++){

ParamArray[i-1+(counter*24)] = rs.getString(i);

System.out.print(rs.getString(i) + '\t');
}
System.out.println();
counter++;
}

} catch(Exception e) {
e.printStackTrace();

} finally {
try
{
if(stmt != null) stmt.close();

if(con != null) con.close();

} catch (Exception exception) {
exception.printStackTrace();
} }


TryBapi sap = new TryBapi(ParamArray);
}
}

When I run the code I do have the following ERROR Message:

java.sql.SQLException: Invalid operation for forward only resultset : last
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
at oracle.jdbc.driver.BaseResultSet.last(BaseResultSet.java:91)
at SarueckConnect.main(SarueckConnect.java:28)

Please could any body Help me out here to figure out how to correct this?
Any Help would be highly apprecited.