Install Mongo

Check mongo status

service mongod status

Creating Users

 security: 
     authorization: disabled

sudo service mongod restart

• Login to mongo by just typing mongo in the command prompt
• create user isuru in mydb database.

use mydb;
db.createUser(
  {
    user: "isuru",
    pwd: "mypwd",
    roles: [ { role: "dbOwner", db: "mydb" } ]
  })

• Change "authorization" to "enabled" in the /etc/mongod.conf to enable authentication. 
• Restart mongo

Login to Mongo with username and password

mongo  -u "isuru" -p "mypwd" --authenticationDatabase "mydb"

MongoDatabase getMongoDatabase() {
        MongoCredential credential = MongoCredential.createCredential(dbUser, dbName, dbPassword);
        ServerAddress serverAddress = new ServerAddress(dbHost);
        List credentialList = new ArrayList<>();
        credentialList.add(credential);

        MongoClient mongoClient = new MongoClient(serverAddress, credentialList);

        return mongoClient.getDatabase(dbName);
    }

#!/bin/sh
export JAVA_HOME=/home/isuru/installs/jdk/jdk1.8.0_101
export PATH=$JAVA_HOME/bin:$PATH

#!/bin/sh
export JAVA_HOME=/home/isuru/installs/jdk/jdk1.7.0_79
export PATH=$JAVA_HOME/bin:$PATH

alias java8='. /home/isuru/stuff/scripts/java8.sh'
alias java7='. /home/isuru/stuff/scripts/java7.sh'

• Create a mobile broadband connection first. You can do it by Edit Connections option.
• In the terminal type lsusb having the dongle plugged in. Below is what I got

• Note the line "Bus 001 Device 007: ID 12d1:1446 Huawei Technologies Co., Ltd. Broadband stick". This is my dongle
• Note these, you need these up ahead. 12d1 is the vendor id, 1446 is the product id. These might change according to your dongle type (this was what they have missed ;))

sudo vi /lib/udev/rules.d/40-usb_modeswitch.rules

• Add following line before "LABEL="modeswitch_rules_end"

ATTR{idVendor}=="12d1", ATTR{idProduct}=="1446", RUN+="usb_modeswitch '%b/%k'"

sudo touch /etc/usb_modeswitch.d/12d1:1446.

• Last step as follows. Same rules apply here for the vendor id and the product id. Additionaly add the prefix "0x" for the vendor id and product id

sudo usb_modeswitch -J -v 0x12d1 -p 0x1446 

.

• I got the below screen and everything was good. 

• I had to issue the command "sudo usb_modeswitch -J -v 0x12d1 -p 0x1446 " always when I restart the machine, but I always believe that having something is better than nothing ;)

What is Cron ?

public class Main {
    public static void main(String[] args) {
        System.out.println("This is how prism looks");
    }
}

Download Prism JS

Add Prism JS to Blogger

• Now we are ready to add Prism to blogger. Go to your blog's Template section. Click on the Backup / Restore button to download the full working template. By doing this, you can restore the template if something goes wrong.
• Now click on Edit Html button. This will take you to the blogger template editor. 
• Locate the </head> tag and add following lines immediate before the </head> tag

<link href='https://dl.dropboxusercontent.com/u/55229039/CDN/prism_custom.css' rel='stylesheet' type='text/css'/>

<script src='https://dl.dropboxusercontent.com/u/55229039/CDN/prism_custom.js' type='text/javascript'/>

• These two links should get from the files we just uploaded to dropbox . 
• Go to your file hosted location in dropbox and click on each of the file and click "Copy public link…" option to get their public link. Add them to your <link> and <script> tags.

• Now save the template and preview it to be sure everything works fine and same as earlier
• If everything goes well, we are done with adding prism to Blogger. Now we simply have to use it in our code.

Using Prism JS to highlight syntax

• Cannot think of a simpler way to highlight syntax. Its just the below code

<pre><code class="language-xxx">### Your code here ###</code></pre>

• The "xxx" is language-xxx should be replaced with the relevant language alias. If it is css

<pre><code class="language-css">p { color: red }</code></pre>

• When you are pasting the code make sure it is encoded properly. If you paste the code to the blog post editor directly when it is in the "Compose" mode, it will encode the code automatically. Or else you can use a tool like this to encode your code.

Prism JS language aliases

maven-resources-plugin

<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>2.5</version>
<executions>
    <execution>
        <id>copy-libs</id>
        <phase>process-resources</phase>
        <goals>
            <goal>copy-resources</goal>
        </goals>
        <configuration>
            <outputDirectory>${basedir}/target/my-project/WEB-INF/lib</outputDirectory>
            <resources>
                <resource>
                    <directory>${deps.home}/lib</directory>
                </resource>
            </resources>
        </configuration>
    </execution>
    <execution>
        <id>copy-xml</id>
        <phase>process-resources</phase>
        <goals>
            <goal>copy-resources</goal>
        </goals>
        <configuration>
            <outputDirectory>${basedir}/target/classes/com/blogspot/techytunes/my-project/dao</outputDirectory>
            <resources>
                <resource>
                    <directory>${basedir}/src/main/java/com/blogspot/techytunes/my-project/dao/</directory>
                    <excludes>
                        <exclude>*.java</exclude>
                    </excludes>
                </resource>
            </resources>
        </configuration>
    </execution>
</executions>
</plugin>

• We need multiple executions ( We need to copy from different sources to different destinations) . That's why we need the <executions> tag. Inside this tag we can define several executions using <execution> tag.
• First, I have to copy some libs. I give an id to that process as <id>copy-libs</id>
• Maven build life cycle has several phases. We need to use "process-resources" phase with the goal "copy-resources"
• When packaging the web-app, maven takes the project folder from the target directory and creates the war file. In my case, it takes the my-project folder and packages its content to a war file. This happens in the package phase.
• We add the basic configuration in the <configuration> tag. <outputDirectory> specifies the destination to copy.
• In the <resources> tag we can add multiple <resource> elements. Everything we put in here, will be copied to the above destination.
• To copy to another destination, we simply need another execution.
• The second execution copy-xml is slightly different from copying resources. Some xml files needed to be copied to the destination of classes. 
• After the process-resources phase there comes compile phase where maven compile all the classes to the target/classes directory. So we take the required xml files and copy them to the relevant destination in the target/classes/... 
• we pick the xml files from src/main/java/com/blogspot/techytunes/my-project/dao and copy them to target/classes/com/blogspot/techytunes/my-project/dao
• In the source directory (src/main/java/com/blogspot/techytunes/my-project/dao) we have .java files along with the xml. We use <excludes> tag to exclude .java files being copied to the destination.
• When maven is in his compile phase, he will compile the classes and put it to the target/classes directory

No 'Access-Control-Allow-Origin' header is present on the requested resource

<filter>
  <filter-name>CorsFilter</filter-name>
  <filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>CorsFilter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

<dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-frontend-simple</artifactId>
            <version>3.0.2</version>
</dependency>

 <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-frontend-jaxws</artifactId>
            <version>3.0.2</version><</dependency>

Setting Up AWS Firewall

Setting up Apache2 and Tomcat

• Apache 2 : 
• sudo apt-get install apache2
• Apache Tomcat 7 : 
• wget http://apache.mirrors.hoobly.com/tomcat/tomcat-7/v7.0.55/bin/apache-tomcat-7.0.55.tar.gz ( you can wget from any download location, it's fine :) )

a2enmod proxy

a2enmod proxy_http

ProxyPass    /the_calling_url    http://the_redirected_url

ProxyPass    /get-all-users    http://localhost:8080/my-app/get-all-users-listener

ProxyPass    /    http://localhost:8080/my-app/get-all-users-listener

ProxyPassReverse / http://localhost:8080/

Tomcat Configuration

<Connector port="8080" protocol="HTTP/1.1"

               connectionTimeout="20000"

               redirectPort="8443"

                proxyPort="80"

        />