[오류] 데이터베이스 연결에 오류가 발생했습니다.

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not

create connection to database server. Attempted reconnect 5 times. Giving up.

        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)

        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Sou

rce)

        at java.lang.reflect.Constructor.newInstance(Unknown Source)

        at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)

        at com.mysql.jdbc.Util.getInstance(Util.java:384)

        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015)

        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)

        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984)

        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:929)

        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2412)

        at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:787)

        at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:49)

        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)

        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Sou

rce)

        at java.lang.reflect.Constructor.newInstance(Unknown Source)

        at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)

        at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:357)

        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java

:285)

        at java.sql.DriverManager.getConnection(Unknown Source)

        at java.sql.DriverManager.getConnection(Unknown Source)

        at database.MYSQL$ThreadLocalConnection.initialValue(MYSQL.java:55)

        at database.MYSQL$ThreadLocalConnection.initialValue(MYSQL.java:40)

        at java.lang.ThreadLocal.setInitialValue(Unknown Source)

        at java.lang.ThreadLocal.get(Unknown Source)

        at database.MYSQL.getConnection(MYSQL.java:31)

        at launch.Start.main(Start.java:60)

Caused by: java.sql.SQLException: Access denied for user 'root'@'localhost' (usi

ng password: YES)

        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1075)

        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3562)

        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3494)

        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:920)

        at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4000)

        at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1285)

        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2338)

        ... 17 more

Exception in thread "main" java.lang.NullPointerException

        at launch.Start.main(Start.java:61)

계속하려면 아무 키나 누르십시오 . . .

sql를 몇번이고 수정했는데 결과가 이꼬라지입니다. 아이고 대체 이게 문제가 뭐고 어떻게 고쳐야 할 까요,