Install Python Specific version upgrade or downgrade and Also Virtual Environment with the specific Python Version

1. install python 3.7 and 3.7 virtual env 

**********************************

sudo add-apt-repository ppa:deadsnakes/ppa

sudo apt update

sudo apt install python3.7

sudo apt install python3.7-venv

2. create environment

*******************

#goto your project root folder

python3.7 -m venv env3.7

source env3.7/bin/activate

now check version, all same

************************

python3 --version

python --version

python3.7 --version

pip --version

pip3 --version

3. upgrade pip

*************

python3.7 -m pip install --upgrade pip

Android Virtual Device - AVD Setup

 1. Install Andriod SDK

2. Set environment for ANDROID_HOME=/home/android/sdk...

3. Install AVD or Android Studio

4. Open Android Studio 

           /home/android-studio/bin/

                        ./studio.sh

5. In that android Studio, you can see Configure Button -> AVD

6. Create Virutal Device or AVD like below. 

7. Start The Emulator by click Play button

8. Add environment variable.

      8.1  goto /etc/profile.d/    [create one file.sh] ex: > sudo vi myenv.sh

         

      export ANDROID_HOME=$HOME/Library/Android/sdk

      export PATH=$PATH:$ANDROID_HOME/emulator
      export PATH=$PATH:$ANDROID_HOME/tools
      export PATH=$PATH:$ANDROID_HOME/tools/bin
      export PATH=$PATH:$ANDROID_HOME/platform-tools

9. > source /etc/profile

Linux Ubuntu - OpenJdk Java 13 Install Setup

To uninstall OpenJDK

> sudo apt-get autoremove openjdk*

> sudo apt-get purge openjdk*

Install > 1.9 JDK 1.3

> sudo apt install -y curl

> curl -O https://download.java.net/java/GA/jdk13/5b8a42f3905b406298b72d750b6919f6/33/GPL/openjdk-13_linux-x64_bin.tar.gz

> tar xvf openjdk-13_linux-x64_bin.tar.gz

> sudo mv jdk-13 /usr/java/

> sudo nano /etc/profile
     # Go to after fi end and paste the below lines
    JAVA_HOME=/usr/java/jdk-13.0.2
    PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
    export JAVA_HOME
    export JRE_HOME
    export PATH


# Configure Java Alternatives
> sudo update-alternatives --install "/usr/bin/java" "java" "/usr/java/jdk-13.0.2/bin/java" 1

# Configure Javac Alternatives
> sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/java/jdk-13.0.2/bin/javac" 1

# Check version
> java -version

# Use only in case of multiple JDKs installed

# Configure Java
> sudo update-alternatives --config java

# Configure Java Compiler
> sudo update-alternatives --config javac

>javac -version

>java version

Apache Kafka - Intall & Setup in Windows

STEPS

1. Download kafka_2.12-2.5.0.zip and extract it [For ex: D:/BigData/kafka_2.12-2.5.0 ]
2. Kafka itself comes with zookeeper, so not necessary to download Zookeeper seperately.
3. Go to Command prompt D:/BigData/kafka_2.12-2.5.0

4. Start zookeeper
5. Start kafka
6. Create Topic
7. Start producer "client" to send data
8. Start consumer "server" to receive those data


Commands from 4th to 8th.

4.  D:\..> start zookeeper-server-start.bat D:\BigData\kafka_2.12-2.5.0\config\zookeeper.properties

5.  D:\..>start kafka-server-start.bat D:\BigData\kafka_2.12-2.5.0\config\server.properties

6.  D:\..>start kafka-topics.bat --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic testtopic

7.  D:\..>start kafka-console-producer.bat --broker-list localhost:9092 -topic testtopic

8. D:\..>start kafka-console-consumer.bat --bootstrap-server localhost:9092 -topic testtopic

Now type something in 7th - CMD prompt.
See the received output in 8th CMD prompt.

All set go.

Note: First stop kafka and then zookeeper. else kafka will keep retrying..