cannot find a valid baseurl for repo

https://unix.stackexchange.com/questions/22924/how-can-i-fix-cannot-find-a-valid-baseurl-for-repo-errors-on-centos
 
For CentOS-7 (1611) version, the ONBOOT=No is located in a file like /etc/sysconfig/network-scripts/ifcfg-enp0s3. I edited that file to ONBOOT=yes and reboot can fix it.

Could not find or load main class Files\Apache

C:\kafka_2.12-2.1.0\config>kafka-server-start  server.properties
The syntax of the command is incorrect.
Error: Could not find or load main class Files\Apache


Ref: https://dzone.com/articles/kafka-setup

better solution to run kafka with zookeeper on windows available here
http://blog.anilot.tk/2014/08/06/Set-Up-Kafka-On-Windows/
https://github.com/Anilot/kafka/releases/


With help of  blog.anilot.tk/2014/08/06/Set-Up-Kafka-On-Windows/, i solved this issue

step 1: Add JRE to path  (C:\Program Files\Java\jdk1.8.0_131\jre\bin )

2. C:\kafka\config\server.properties

add this line
log.dirs=C:\kafka\kafka-logs

3. zookeeper.properties configur
Similar work
dataDir=C:\kafka\zookeeper-data


4. Start Zookeeper

C:\kafka>.\bin\windows\zookeeper-server-start.bat .\config\zookeeper.properties

run with admin power, 
5. Start Kafka

C:\kafka>bin\windows\kafka-server-start.bat config\server.properties

it is working for me
========================================================

running zookeeper on windows

1. download zk (zookeeper )

2. Extract and put it in some place like : C:\zookeeper-3.4.10\

3. Add to path : C:\zookeeper-3.4.10\bin

4. Change configuration in C:\zookeeper-3.4.10\conf\zoo_sample.cfg to zoo.cfg
this configuration is nothing to do except renaming

5. Now run the server all the command are available in C:\zookeeper-3.4.10\bin  folder

C:\Users\ycs-gbs>zkServer

6. you can run other commands
C:\Users\ycs-gbs>zkCli


good ref: https://medium.com/@shaaslam/installing-apache-zookeeper-on-windows-45eda303e835

https://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html#sc_RunningReplicatedZooKeeper

https://curator.apache.org/curator-framework/index.html

http://highscalability.com/blog/2008/7/15/zookeeper-a-reliable-scalable-distributed-coordination-syste.html

cannot find symbol [ERROR] symbol: class slf4j

Compilation failure
[ERROR] /E:/me/me/src/main/java/com/me/me/DemoApplication.java:[13,2] cannot find symbol
[ERROR]   symbol: class slf4j

add this import and its dependency

import lombok.extern.slf4j.Slf4j;

value == null || items.where((DropdownMenuItem item) => item.value == value).length == 1

I/flutter (23889): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (23889): The following assertion was thrown building DropdownButtonFormField<dynamic>(dirty, state:
I/flutter (23889): _DropdownButtonFormFieldState<dynamic>#94f46):
I/flutter (23889): 'package:flutter/src/material/dropdown.dart': Failed assertion: line 514 pos 15: 'items == null ||
I/flutter (23889): value == null || items.where((DropdownMenuItem<T> item) => item.value == value).length == 1': is not
I/flutter (23889): true.


........................'

use init state to initialize value part in

buildDropdownButtonFormField

void initState() {

String x = controller.text; //on update initial value

x = x.trim();

if (x != "" && x != null) {

selectBoxvalue = x;

}

super.initState();

}

buildDropdownButtonFormField(BuildContext context) {

return DropdownButtonFormField(

items: dropDownList.toList(),

decoration: InputDecoration(

labelText: Translations.of(context).text(label),

),

onChanged: (value) {

setState(() {

selectBoxvalue = value;

});

if (controller != null) {

controller.text = value;

}

if (onChangeSelectMap != null) {

onChangeSelectMap(value);

}

},

value: selectBoxvalue ?? null,

);

}

select box flutter

FormField(
        initialValue: initialValue,
        builder: (FormFieldState state) {
          return InputDecorator(
            decoration: InputDecoration(
              labelText: Translations.of(context).text(label),
            ),
            child: DropdownButtonHideUnderline(
              child: DropdownButton(
                value: selectBoxvalue ?? null,
                items: dropDownList.toList(),
                onChanged: (value) {
                  setState(() {
                    selectBoxvalue = value;
                  });

                  if (controller != null) {
                    controller.text = value;
                  }

                  if (onChangeSelectMap != null) {
                    onChangeSelectMap(value);
                  }
                },
              ),
            ),
          );
        });


///////////////////////////

map.forEach((k, v) {
      dropDownList.add(DropdownMenuItem(
        value: k,
        child: new Text(v),
      ));
    });
////////////////////////////////

Al6Fe xrd teo theta values

11.856899488926743 15.332197614991486 23.91822827938671 40.2725724020443 http://arohatgi.info/WebPlotDigitizer/app/ https://astamuse.com/ja/drawing/JP/2014/224/290/A/000006.png Al6Fe 27.191642594278026 29.240235843456922 31.638241462546 34.152981678603936 35.83237703296268 http://www.scielo.br/img/revistas/mr/v18s2//1516-1439-mr-1516-1439346114-gf07.jpg