The Daily Programming

Sometime we need to convert Output Stream to Input Stream. We can perform the conversion multiple ways.  The following two approaches are most popular: 1. ByteArrayOutputStream to ByteArrayInputStream 2. PipedOutputStream to PipedInputStream Complete example code is available in the [ Github ]. Approach 1: ByteArrayOutputStream/ByteArrayInputStream The ByteArrayOutputStream/ByteArrayInputStream is the easiest way to convert OutputStream to InputStream. Code snippet: TextWriter textWriterBins = new TextWriter(); ByteArrayOutputStream bouts = new ByteArrayOutputStream(); textWriterBins.write(bouts); ByteArrayInputStream bins = new ByteArrayInputStream(bouts.toByteArray()); TextReader textReader = new TextReader(bins); textReader.print(); Here, TextWriter is a class which writes some text in the OutputStream and TextReader is a class which reads data from InputStream and print on the console. In the above code snippet, the TextWriter.write method writes the da...

In this post, I would like to share my story about external configuration file of Log4J2. I developed a Java web application in WildFly 19 application server. It was my pet project. I followed few strict rules about 3rd party libraries. For example, I did not use log4j2-web library/jar file. It was the challenge because in some workplace you cannot have luxury to get all bells and whistle. You have to accept the situation. Therefore, I took this challenge to use external configuration file of Log4J2 in the web application without depending on log4j2-web jar file. My development environment's logging configuration is not same as production environment. In this case, I do not want to swap between development configuration and production configuration file during deployment.    The above situation can be mitigate by two ways: Use external logging configuration file. User application server specific logging system. For exampke, ...

Today, I merged my brother's coverletter and resume into one single pdf file. How did I merge two pdfs? Hmmm.... Did I buy Adobe Acrobat professional.........Oh no!!!!. I am Linux user. I can do magic. Sorry Windows users..... I am using Linux mint. I have pdftk tool. Type the following command in the terminal to install pdftk: $ sudo apt-get install pdftk Firstly, I renamed my brother's coverletter from "lastname-firstname-coverletter.pdf" to "lastname-firstname-1.pdf" and resume from "lastname-firstname-resume.pdf" to "lastname-firstname-2.pdf" Finally, I ran the following command in the terminal pdftk lastname-firstname-*.pdf cat output lastname-firstname-coverletter_resume.pdf

This is a quick YAML tutorial: https://learnxinyminutes.com/docs/yaml/

Here, I will discuss how to create mongo shard in the single machine (locally) for dev environment. My OS is Linux Mint and MongoDB version is 4+. Install MongoDB: I downloaded mongodb tar files and extracted it to the /opt/mongo/. Create database directory: $mkdir -p /opt/mongo_db/shard_db I like /opt directory very much, if you do not like create your database directory in /opt, please create it in your desire location. I dislike pointless argument. To create shard you must have a plan to organize your shard clusters. In this example, I will create 3 shard each shard will have 2 replicate sets and 1 config server with 2 replicate sets and 1 mongos to connect shard cluster via config server 1) Shard servers/clusters   1.1) Create sdb directory inside the shard_db/ directory:          $mkdir sdb     1.2) Inside sdb/ directory we are going to create 6 directories as I mentioned earlier that I am going to create 3 shard with 2 re...

Few days ago, I have to download Spring Framework latest stable jars. There is no single zip file which contains all the jars of Spring Framework. So, I have to create the directory for specific jar and download it.  I had older version of Spring Framework directory which contains folder for specific jar file. I do not want copy the content inside the directory just directory structure. Therefore, I issued the following command. find . -type d >dirs.txt xargs mkdir -p