Problem with preparedstatement and execute method in jdbc

package sql;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class ConnectionDemo {
	
	 public static void main(String[] args) {
	
		 try {
			Class.forName("oracle.jdbc.driver.OracleDriver");
			 Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE","system","9848451415");
			 PreparedStatement st = con.prepareStatement("insert into emp(empno,ename) values(?,?)");
			 st.setInt(1, 3);
			 st.setString(2, "Naresh");
			 if(st.execute()){
				 System.out.println("Successfull executed");
			 }
			 else
				 System.out.println("Failed");
			
			 
		 }	 
		 catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		 
		 
		 
	 } 
}