JDBC连接数据库出现空指针异常

JDBC连接数据库出现空指针异常
连接器版本5.1，jdk版本1.8，数据库用的是mariadb10.11
代码如下

import java.sql.Connection;
import java.sql.DriverManager;

public class JdbcDemo1 {
    public static void main(String[] args) {    
        String driver = "com.mysql.jdbc.Driver";
        
        String URL = "jdbc:mysql://localhost:3306/mydb1";
        Connection conn = null;
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            System.out.println("驱动启动失败");
        }
        
        try {
            
            conn = DriverManager.getConnection(URL, "root", "admin");
            System.out.println("数据库连接成功");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            System.out.println("数据库连接失败");
            e.printStackTrace();
        }
    }
}

正常访问数据库没问题，在eclipse中把密码故意改错，会报如下错误

数据库连接失败
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1086)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4237)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4169)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:928)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1750)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1290)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2493)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2526)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2311)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:347)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.tedu.jdbc.JdbcDemo1.main(JdbcDemo1.java:21)

输入正确密码则报空指针异常，如下

数据库连接失败
java.sql.SQLException: java.lang.NullPointerException
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1086)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)
    at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1074)
    at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3600)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2541)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2311)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:347)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.tedu.jdbc.JdbcDemo1.main(JdbcDemo1.java:21)
Caused by: java.lang.NullPointerException
    at java.util.TreeMap.put(TreeMap.java:563)
    at com.mysql.jdbc.Util.resultSetToMap(Util.java:508)
    at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1004)
    ... 15 more

两天了，在网上试了各种方法还是找不到问题在哪，希望有经验的朋友帮忙指点指点。。

mariadb使用这些参数连接：
String driver = "org.mariadb.jdbc.Driver";
String URL = "jdbc:mariadb://localhost:3306/mydb1";

所以你的数据库到底是mariadb还是 mysql呢