从数据库中获取值时线程主java.lang.NullPointerException中的异常

我只是想在eclipse上运行一个有问题的Java程序，但是却收到NullPointerException。我的代码发布在下面。请告诉我我做错了什么。

Rect.java

package org.spring.model;

public class Rect {

    private int id;
    private String name;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public Rect(int rectId, String rectName)
    {
        setId(rectId);
        setName(rectName);
    }


}

JdbcDaoImplement.java

    package org.spring.dao;

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

    import org.spring.model.Rect;

public class JdbcDaoImplement {

    public Rect getRect(int rectId)
    {
        Connection conn=null;

        try
        {
            Class.forName("oracle.jdbc.OracleDriver");
            String jdbcUrl = "jdbc:oracle:thin:@localhost:1521:ORCL";
            conn = DriverManager.getConnection(jdbcUrl, "system", "abcd");
            PreparedStatement ps=conn.prepareStatement("SELECT * FROM RECTANGLE WHERE id=?");
            ps.setInt(1, rectId);

            Rect rect=null;
            ResultSet rs=ps.executeQuery();
            if(rs.next()==true)
            {
                rect=new Rect(rectId,rs.getString("name"));
            }
            rs.close();
            ps.close();
            return rect;
        }
        catch(Exception e)
        {
            throw new RuntimeException();
        }
        finally
        {
            try {
                conn.close();
            } catch (SQLException e) {
                //e.printStackTrace();

            }
        }
    }

}

最后是JdbcDemo.java

package org.spring;

import org.spring.dao.JdbcDaoImplement;
import org.spring.model.Rect;

public class JdbcDemo {

    public static void main(String[] args) {
        Rect rect=new JdbcDaoImplement().getRect(1);
        System.out.println(rect.getName());
    }

}

堆栈跟踪为：

Exception in thread "main" java.lang.NullPointerException
    at org.spring.JdbcDemo.main(JdbcDemo.java:10)