I needed to install a local jar file into my laptop’s local maven repository and found this article. I used this approach to install this jar file in my repo:
mvn install:install-file -Dfile=my-model-1.2.1.jar -DgroupId=com.cyberaka.my.package -DartifactId=my-model -Dversion=1.2.1 -Dpackaging=jar -DgeneratePom=true
This duly added the local jar file under appropriate group id and artifact id inside my maven repository and I was able to refer to this dependency through my project’s pom.
Lets say I have two servers running on my laptop
1. http://localhost:3000 – This is the UI
2. http://localhost:4000 – This is the web services API
So now I need to setup something like this:
1. http://localhost/ – This should point to UI
2. http://localhost/api/ – This should point to web services API
To set this up I have used NGINX and added this section in the “server” section of the nginx.conf file. On my Mac system this file is located at: /usr/local/etc/nginx/nginx.conf
location /api/ {
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://localhost:4000/;
}
location / {
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://localhost:3000/;
}
To reload NGINX I use the “-s reload” parameter for nginx. On my Mac I execute this command:
/usr/local/Cellar/nginx/1.10.0/bin/nginx -s reload
Lets say I type something in Hindi and the outcome is listed below:
तीन व्याकितियों की औसत आयु ३३ वर्ष है.
In Hex View it will look like:
e0 a4 a4 e0 a5 80 e0 a4 a8 20 e0 a4 b5 e0 a5 8d e0 a4 af e0 a4 be e0 a4 95 e0 a4 bf e0 a4 a4 e0 a4 bf e0 a4 af e0 a5 8b e0 a4 82 20 e0 a4 95 e0 a5 80 20 e0 a4 94 e0 a4 b8 e0 a4 a4 20 e0 a4 86 e0 a4 af e0 a5 81 20 e0 a5 a9 e0 a5 a9 20 e0 a4 b5 e0 a4 b0 e0 a5 8d e0 a4 b7 20 e0 a4 b9 e0 a5 88 2e e0 a4 85 e0 a4 97 e0 a4 b0 20 e0 a4 89 e0 a4 a8 e0 a4 95 e0 a5 80 20 e0 a4 86 e0 a4 af e0 a5 81 20 e0 a5 a8 3a e0 a5 a9 3a e0 a5 aa 20 e0 a4 95 e0 a5 87 20 e0 a4 85 e0 a4 a8 e0 a5 81 e0 a4 aa e0 a4 be e0 a4 a4 20 e0 a4 ae e0 a5 87 e0 a4 82 20 e0 a4 b9 e0 a5 8b 2c e0 a4 a4 e0 a5 8b e0 a4 b9 20 e0 a4 89 e0 a4 a8 e0 a4 ae e0 a5 87 20 e0 a4 b8 e0 a5 87 20 e0 a4 b8 e0 a4 ac e0 a4 b8 e0 a5 87 20 e0 a4 ac e0 a5 9c e0 a5 87 20 e0 a4 95 e0 a5 80 20 e0 a4 86 e0 a4 af e0 a5 81 20 e0 a4 95 e0 a4 bf e0 a4 af e0 a5 8d e0 a4 a4 e0 a4 a8 e0 a5 87 20 e0 a4 b5 e0 a4 b0 e0 a5 8d e0 a4 b7 20 e0 a4 b9 e0 a5 8b e0 a4 97 e0 a5 80 3f
The main thing to notice here is that every hindi character is starting with the byte “E0”. This is basically a code point which identifies the code size of the UTF-8 character. The following table appropriate highlights it:
Binary Hex Comments
0xxxxxxx 0x00..0x7F Only byte of a 1-byte character encoding
10xxxxxx 0x80..0xBF Continuation bytes (1-3 continuation bytes)
110xxxxx 0xC0..0xDF First byte of a 2-byte character encoding
1110xxxx 0xE0..0xEF First byte of a 3-byte character encoding
11110xxx 0xF0..0xF4 First byte of a 4-byte character encoding
Reference: https://stackoverflow.com/questions/5290182/how-many-bytes-does-one-unicode-character-take/33349765#33349765
I needed to email an HTML report and I was not happy with the fact that we have to create zip file containing the HTML, Images etc. I knew it was possible to embed base64 data directly into HTML I started looking for some PoC. My search took me to an online base64 encoder and decoder. This gave me the idea to convert the external image files into base64 string and embed it directly into HTML. On some search I landed up Apache Commons Codec Library which contains a Base64 class which can be used to covert an input stream into a base64 string.
I recently received a couple of REST Web Service endpoints where the implementation technology was not Java. So I had to either rollout my own object and then rely on the object mapper to map the JSON to Java or come up with an approach to generate the relevant POJO file. On a little bit of looking around I found out the following two links for generating Java Code from JSON.
http://json2java.azurewebsites.net/
https://javafromjson.dashingrocket.com/
The POJO generated were decent and got the job done. I didn’t have to write the POJO myself and the code generated by these websites did the job well.
Another link recommended in the posts comments.
http://www.freecodeformat.com/json2pojo.php (Thanks Daniel)
I found out the 1st two links are no longer working. So I found out about another tool based on Visual Studio Code. Use the following extension for solving this use case.
https://marketplace.visualstudio.com/items?itemName=quicktype.quicktype
Sometimes we want to clean out our Git workspace and remove any file which is untracked. A hard reset usually does the job for modified files as shown below:
git reset --hard
But hard reset doesn’t fit in case of untracked files. The following command will do the job:
git clean -d -fx ""
-x means ignored files are also removed as well as files unknown to git.
-d means remove untracked directories in addition to untracked files.
-f is required to force it to run.
Reference:
https://www.kernel.org/pub/software/scm/git/docs/git-clean.html
Since I like working using terminal I prefer to do all my operations of git from the command prompt. The first prerequisite to this is to have my name and email configured. This few commands are required to do this simple operation:
To set the name and email:
git config --global user.name "Your Name"
git config --global user.email "Your Email"
To view the name and email which is known to git execute the same commands without any parameter as shown below:
git config --global user.name
git config --global user.email
Many times there are some Java linkage errors and I have to find out in which jar files the class files are located. So this has lead me to find out tools which can do this job for me. I usually get the job done by using this excellent open source tools named Jar Explorer inside Github. It is basically a platform independent Swing based utility which allows you to recursively search inside Jar files located inside a folder for any class name String. So it is possible for me to search for a class named “LoggingEvent” inside a folder containing lots of jars and it outputs the list of all the jar files where it found classes containing the text “LoggingEvent”.
However when you are connected to Linux consoles using ssh and don’t have access to X Windowing system then you have to rely on either text based java program or pure vanilla shell scripting. For this situation I use the following snippets of code which I found from a Stackoverflow article.
On Linux/Mac
for i in *.jar; do jar -tvf "$i" | grep -Hsi ClassName && echo "$i"; done
On Windows
for /R %G in (*.jar) do @jar -tvf "%G" | find "ClassName" > NUL && echo %G
I use Fiddler extensively in Windows for debugging any HTTP traffic in my web applications. However on Mac Fiddler is not available. On some search I have found out the following tools which can do the job:
Chrome
In Chrome just type “chrome://net-internals/#http2” in the address bar and you will be able to see all the HTTP traffic that is going on in your system. Not sure when it got added to Chrome but it is a very simple yet powerful utility.
Charles Proxy
This is Java based commercial utility which can be used for almost Fiddler like functionality. This works in Windows, Linux and Mac so it is good deal I think for any developer.
Update: On using Charles Proxy I found it to be dead simple to use and it fulfilled all the requirements I had on my Mac. There is 30 minute lockout feature for unlicensed version which seems fair. It is completely worth the 50$ price tag.
I wanted to try out Tomcat 8 and Java 8 for one of my production servers. The following link summarizes the various steps required for installing and configuring both Java 8 and Tomcat 8 from scratch.