Error when trying java dhtmlxConnector sample

I’m trying to try java dhtmlxConnector sample,
i already import the sample.war, create the database in mysql, running the dump.sql script, change the username and password in databaseconnection.java.
but when running the sample i got error like below :

java.sql.SQLException: Access denied for user ‘root’@‘localhost’ (using password: NO)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3593)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3525)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:931)
at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4031)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1296)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2338)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2371)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2163)
at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:794)
at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:407)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:378)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at DataBaseConnection.getConnection(DataBaseConnection.java:9)
at Grid_01_BasicConnector.configure(Grid_01_BasicConnector.java:20)
at com.dhtmlx.connector.ConnectorServlet.doGet(ConnectorServlet.java:28)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:879)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)

can someone tell me the solution?
Thx
Charles

It seems that provided user|password info is not valid for connection to the database.
Check \WEB-INF\src\DataBaseConnection.java - in this file you can change the user and password values to the correct ones.

Thx for reply, i already change the username and password in \WEB-INF\src\DataBaseConnection.java, but still error.

is there some mistakes that i do when importing samples.war?
i’m using eclipse.

The above stack trace clearly shows to DB login error

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: NO)

Maybe login in question is limited to specific hosts, and not allowed from the PC in question