How can I to do For DataView reload

Hi,Long time no see,I used Dhtmlx from 3.6 to now.I’ve found a lot of change,I’m not very comfortable.So,I used Dhtmlx 6.4.2 for suite_gpl.I have a few questions
1.Where the funciton for load xml files;
2.How can I to do For DataView reload data;
3.How can I to do For Change CSS.
4.Where the Java Connector for Dhtmlx 6.4.2

1.Where the funciton for load xml files;

Loading the data from the xml files aurrtently is avaialble in PRO version only:
https://docs.dhtmlx.com/suite/helpers__datadrivers.html#xmlformat

2.How can I to do For DataView reload data;

All the data components of new dhtmlxSuite 6 use the dataCOllection helper to operate with the data.
https://docs.dhtmlx.com/suite/data_collection__api__refs__datacollection.html
It allows to unify the API and use teh common data fromat for any dhtmlx component.
So, to reload the dataview data you need to call:

dataView.data.removeAll()
dataView.data.load(url)

3.How can I to do For Change CSS.

Could you please, clarify what component you want to modify and the changes you are interested in.
Each component has the following individual article in the docs:
https://docs.dhtmlx.com/suite/dataview__customization.html
explaining the basic css classes of the component.

4.Where the Java Connector for Dhtmlx 6.4.2

There is no connectors for the dhtmlxSuite 6 compoents.
dataCollection support Rest API so it is indifferent to the using backend. All yuou need to do is to generate a valid JSOIN and can be loaded to your dhtmlxComponent.

Thanks.Thank you very much.