Error In Spring Using JDBC

public class StudentJDBCTemplate implements StudentDao

above class giving error as

The type StudentJDBCTemplate must implement the inherited abstract method

StudentDao.listStudents()

Interface is as below

import java.util.List;
import javax.sql.DataSource;
public interface StudentDao {
public void setDataSource(DataSource ds);
public void Create(String Name,Integer age);
public void getStudent(Integer id);
public List<Student>listStudents();
public void delete(Integer id);
public void update(Integer id,Integer age);
}