Mainly Spring/Java and Java JEE tips and tutorials based on what i'm working on, usually (Spring, MongoDB, Spring boot, Big Data, Cassandra etc.) or what interests me.
Occasionally some gadget tips.
//load the configuration file from the classpath
val conf = ConfigFactory.load
The convenience method ConfigFactory.load() loads the following (first-listed are higher priority):
system properties
application.conf (all resources on classpath with this name)
application.json (all resources on classpath with this name)
application.properties (all resources on classpath with this name)
reference.conf (all resources on classpath with this name)
The idea is that libraries and frameworks should ship with a reference.conf in their jar. Applications should provide an application.conf, or if they want to create multiple configurations in a single JVM, they could use ConfigFactory.load("myapp") to load their own myapp.conf. (Applications can provide a reference.conf also if they want, but you may not find it necessary to separate it from application.conf.)
3.- Reading the configuration file values
//retrieve configuration files values
val remoteIp = conf.getString("server.ip")
val remotePort = conf.getInt("server.port")
Recently I had a problem with my mac, my wifi connection was working properly but my ethernet connection was not it was getting a self-assigned IP. After checking the obvious culprits (cable, router, switch) it turns out that the problem was elsewhere.
After searching the internet I realized that I wasn't the only one having this problem, and there are a lot of fixes such as :
Deleting the "/Machintosh HD/Library/Preferences/com.apple.alf.plist" and rebooting
Resetting the PRAM
Recreating a network configuration
By chance I decided to try and disable IPv6 on the network interfaces like so :
Recently a change was made in my company in the way the SVN repositories were handled; as a result we had to change the accounts we used to access the repos
Whenever I tried pulling or pushing info into those repositories I was getting errors like :
RA layer request failed: PROPFIND request failed on '/svn/2001/ufasoli/myproject/trunk': PROPFIND of '/svn/2001/ufasoli/myproject/trunk'
: 403 Forbidden (https://internal.svn.com) at /lib/Git/SVN.pm line 717
I realized that it was because the credential information was cached locally on the machine, so the system was sending old information , the tricky part was that the old accounts allowed authentication on the repositories, they were just no longer authorized to do anything on them, so I was getting an HTTP 403 error and the system was not prompting me for a new password (since the old accounts could still log in...)
So this is how I fixed it on my windows machine:
Under your user folder you should have a folder where subversion stores cached data C:\Users\ulf\.subversion (in my case)
This folder contains an auth folder were you will normally find another 3 folders :
svn.simple
svn.ssl.server
svn.username
To delete the cached credentials you can delete the content of the following folders :
svn.simple
svn.ssl.server
Once this folders deleted git should prompt you again for your username/password
Now copy the entire contents of the c:/tmp/git/git under c:/tmp/git/msygit-env/git
4. Build Git
Now you can fire up a DOS console and head up to the msysgit and build Git
cd c:/tmp/git/msygit-env
msys.bat
Once the build starts you should see some output similar to
-------------------------------------------------------
Building and Installing Git
-------------------------------------------------------
GIT_VERSION = 2.1.0
* new build flags
CC credential-store.o
* new link flags
CC abspath.o
CC advice.o
CC alias.o
CC alloc.o
CC archive.o
CC archive-tar.o
5. Moving the binaries and updating the path
Once the build is finished you will find the git binaires under the /bin folder
So let's say for example that I want to put my git binaries under c:/dev/bin/git2 go ahead and copy the following folders from the c:/tmp/git/msygit-env/git :
bin
cmd
etc
include
lib
libexec
mingw
share
ssl
Please note that I don't think you actually need all those folders but I copied them all just to be sure ..
Now for the final step the PATH; you will need to add the following folders to your PATH :
When using NodeJS's HTTP module to query you might end-up having performance problems if you do some heavy HTTP querying.
By default when executing queries using the HTTP module NodeJS will use connection pooling with the maximum number of connection sockets being 5, so if you hit the bottleneck your HTTP queries will lag as they will be queued.
To my knowledge you have 2 options to "counter" this behavior :
Increase the number of http sockets
Disable the HTTP agent per request
1. Increase the number of http sockets
var http = require('http');
// increase the maximum number of http connections in the pool
http.globalAgent.maxSockets = 100;
//regular http request options
var options = {
port: 1337,
hostname: '127.0.0.1',
method: 'GET',
path: '/test'
};
// make http query
var req = http.request(options, function(res) {
console.log('STATUS: ' + res.statusCode);
console.log('HEADERS: ' + JSON.stringify(res.headers));
res.setEncoding('utf8');
res.on('data', function (chunk) {
console.log('BODY: ' + chunk);
});
});
2.Disable the HTTP agent per request
var http = require('http');
//regular http request options
var options = {
port: 1337,
hostname: '127.0.0.1',
method: 'GET',
path: '/test',
agent:false //disable the nodejs agent (no connection pooling)
};
// make http query
var req = http.request(options, function(res) {
console.log('STATUS: ' + res.statusCode);
console.log('HEADERS: ' + JSON.stringify(res.headers));
res.setEncoding('utf8');
res.on('data', function (chunk) {
console.log('BODY: ' + chunk);
});
});
Please be aware that changing this options might have side effects on your host system such as higher memory and bandwidth use so use it wisely
As covered in a previous article (here and here) spring-boot is a very useful framework when working on full enabled Spring projects
Recently I wasted some time with yet another encoding problem.. where all my accentuated and special characters where corrupted.
I was using the data.sql convention that states that if a file named data.sql is found in the CLASSPATH spring will use this file to bootstrap the database, my SQL file was properly encoded in UTF-8 as well as my maven-resources-plugin however the data recovered from the database was corrupted (accents and special characters where broken)
After reading a bit the documentation I found out that the source of the problem was at the moment of reading the SQL file that the encoding was causing trouble.. thankfully you can fix this one pretty easlily by changing one property value :
spring.datasource.sqlScriptEncoding=UTF-8
spring-boot has a lot of useful properties that allow you to tune the framework which you can find here
It's not uncommon to need a custom packaging or assembly for a given project for some reason or another, this can be accomplished in a certain number of ways
Recently I needed an application to be packaged as the following structure :
The Assembly Plugin for Maven is primarily intended to allow users to aggregate the project output along with its dependencies, modules, site documentation, and other files into a single distributable archive.
Your project can build distribution assemblies easily, using one of the convenient, prefabricated assembly descriptors.
These descriptors handle many common operations, such as packaging a project's artifact along with generated documentation into a single ZIP archive. Alternatively, your project can provide its own descriptor and assume a much higher level of control over how dependencies, modules, file-sets, and individual files are packaged in the assembly.
Currently the plugin can create distributions in the following formats:
zip
tar
tar.gz
tar.bz2
jar
dir
war
format that the ArchiveManager has been configured
For this tutorial we will be using the dir format in order to output the project structure described above
Let's start with the easy part first, the maven assembly plugin configuration where we will tell the plugin where to find our assembly file and where to output the result of the assembly operation
Now since in our case we want all the files in the resource directory to be handled by the assembly plugin we will configure the maven resources plugin to ignore everything inside the resources folder (please note that this is an optional step and it might not apply to your project)
...
${basedir}/src/main/resources**/**
...
Once the maven part is done we can get started with the core code
If you remember we will end up with a runnable JAR file so go ahead and create a Main class like so :
package com.ufasoli.maven.custom.assembly;
/**
* User: Ulises Fasoli
* Date: 23.06.2014
* Time: 18:03
* Project : maven-custom-assembly
*/
public class Main {
public static void main(String[] args) {
System.out.println("HELLO WORLD !");
}
}
Since this is going to be a runnable JAR file we will need to configure the maven JAR plugin to generate the manifest file with our main class
