程序总是报错，“java.lang.NoSuchMethodError: main Exception in thread "main" ”。问题出在哪里？

package com.globalite.dangdang.framework;

import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import com.sun.org.apache.xpath.internal.operations.String;

public class JDBCManager {

public static void main(String[] args) {
{
Connection ct=null;
Statement sm=null;
ResultSet rs ;

try{
Class.forName("oracle.jdbc.driver.OracleDriver");
ct = DriverManager.getConnection("jdbc:oracle:thin@127.0.0.1:1521:ORCL", "DangDang","Qweasd");
sm = ct.createStatement();
rs = sm.executeQuery("select id, name from book");
while (rs.next()) {
//用户名
System.out.println("用户名： "+rs.getString(1));
//默认是从1开始编号的
}
}
catch(SQLException e)
{
e.printStackTrace();
} catch (ClassNotFoundException e) {

e.printStackTrace();
}
finally
{

}}
}
}

1）import com.sun.org.apache.xpath.internal.operations.String;
将上面这条import语句去掉。
2）ct = DriverManager.getConnection("jdbc:oracle:thin@127.0.0.1:1521:ORCL","DangDang","Qweasd");
改为
ct = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:ORCL","DangDang","Qweasd");
thin后面少了一个冒号

你的程序我运行通过了是环境变量设置的问题 classpath: .;c:\jsdk\lib\dt.jar;c:\jsdk\lib\tools.jar path: 原先的内容;c:\jsdk\bin

删掉这句 import com.sun.org.apache.xpath.internal.operations.String;