java 中import java.sql.Connection 报错：The import java.sql.Connection conflicts with a type defined in the same file

java里面import java.util.*;是什么用处 import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.sql.*; public class a import java.util.* 表示什么.. java 中import javax.swing.JOptionPane;什么意思 android的log中没有输出package mars.activity;import java.util.ArrayList;import java.util.HashMap;import android.app.Activity;import android.app.ListActivity;import android.os.Bundle;import android.view.View;import android.widget.ListView;import 求解释import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; java 中import java.sql.Connection 报错：The import java.sql.Connection conflicts with a type defined in the same file java 中 java java import java.util.Date表示什么意思,java里的. 英语翻译import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.border.*;import java.util.Vector;import java.net.*;import java.io.*;class FindFriend2 extends JFrame {//查找好友类JLabel jLabel1 = new JLabel();JButton The import java.awt is never used 要详细点的哈 我是新手 不太懂哦// Java core packagesimport java.awt.*;import java.awt.event.*;import java.awt.geom.*;import java.util.*;// Java extension packagesimport javax.swing.*;import javax.swing.BorderFactory;import javax.swing.ev java 画矩形package testFrame;import java.awt.Color;import java.awt.Component;import java.awt.Frame;import java.awt.Graphics;import java.awt.Rectangle;public class FrameTest extends Frame {/*** @param args*/Rectangle rec;Frame f;public void paint(G import java.io.IOException;import java.io.OutputStream;import java.net.Socket;import java.net.UnknownHostException;import java.sql.ResultSet;import org.sql.IntoDB;public class BaiduReferer {public static void main(String[] args) throws UnknownHostExc import=java.sql.*和import=java.util.* 有什么区别? import java.awt.*import java.awt.event.*为什么还要下面的那个语句.?