An architectural overview of Spring Web MVC

Model-View-Controller (MVC) pattern


 Spring Web MVC Architecture









image courtesy  : spring in practice (Willie Wheeler)

Introduction to the Project Object Model

POM (Project Object Model) is an xml file which contains the project configuration details used by Maven. It defines the model of the project which provides the entire configuration required for a project. In maven based development the jars, libraries that required, are added to the project using this pom.xml. In the POM context we call those jars, libraries as Dependencies.

How to manually install libraries(.jars) to local maven repository

If you don't have the JAR in your repository you can however install it.

Command-

mvn install:install-file -Dfile=<path-to-file> -DgroupId=<group-id> -DartifactId=<artifact-id> -Dversion=<version> -Dpackaging=<packaging> -DgeneratePom=true

Where: <path-to-file>  the path to the file to load

       <group-id>      the group that the file should be registered under

       <artifact-id>   the artifact name for the file

       <version>       the version of the file

       <packaging>     the packaging of the file e.g. jar

For example I will use  kaptcha, a popular third party Java library.
 C:\>mvn install:install-file -Dfile=c:\kaptcha-2.3.jar -DgroupId=com.google.code
-DartifactId=kaptcha -Dversion=2.3 -Dpackaging=jar

After installed, just declares the kaptcha coordinate in pom.xml.

  <dependency>
      <groupId>com.google.code</groupId>
      <artifactId>kaptcha</artifactId>
      <version>2.3</version>
 </dependency>

A list of HTTP status codes

100	Continue	Only a part of the request has been received by the server, but as long as it has not been rejected, the client should continue with the request
101	Switching Protocols	The server switches protocol.
200	OK	The request is OK
201	Created	The request is complete, and a new resource is created
202	Accepted	The request is accepted for processing, but the processing is not complete.
203	Non-authoritative Information
204	No Content
205	Reset Content
206	Partial Content
300	Multiple Choices	A link list. The user can select a link and go to that location. Maximum five addresses
301	Moved Permanently	The requested page has moved to a new url
302	Found	The requested page has moved temporarily to a new url
303	See Other	The requested page can be found under a different url
304	Not Modified
305	Use Proxy
306	Unused	This code was used in a previous version. It is no longer used, but the code is reserved.
307	Temporary Redirect	The requested page has moved temporarily to a new url.
400	Bad Request	The server did not understand the request
401	Unauthorized	The requested page needs a username and a password
402	Payment Required	You can not use this code yet
403	Forbidden	Access is forbidden to the requested page
404	Not Found	The server can not find the requested page.
405	Method Not Allowed	The method specified in the request is not allowed.
406	Not Acceptable	The server can only generate a response that is not accepted by the client.
407	Proxy Authentication Required	You must authenticate with a proxy server before this request can be served.
408	Request Timeout	The request took longer than the server was prepared to wait.
409	Conflict	The request could not be completed because of a conflict.
410	Gone	The requested page is no longer available.
411	Length Required	The "Content-Length" is not defined. The server will not accept the request without it.
412	Precondition Failed	The precondition given in the request evaluated to false by the server.
413	Request Entity Too Large	The server will not accept the request, because the request entity is too large.
414	Request-url Too Long	The server will not accept the request, because the url is too long. Occurs when you convert a "post" request to a "get" request with a long query information.
415	Unsupported Media Type	The server will not accept the request, because the media type is not supported.
417	Expectation Failed
500	Internal Server Error	The request was not completed. The server met an unexpected condition
501	Not Implemented	The request was not completed. The server did not support the functionality required.
502	Bad Gateway	The request was not completed. The server received an invalid response from the upstream server
503	Service Unavailable	The request was not completed. The server is temporarily overloading or down.
504	Gateway Timeout	The gateway has timed out.
505	HTTP Version Not Supported	The server does not support the "http protocol" version.

A Look At The Uptime Of 50 Popular APIs

Application Programming Interface (API) is a specification of how some software components should interact with each other.In practice in most of the cases an API is a library that usually includes specification for routines, data structures, object classes, and variables.
You Can find any API from following link....cheers!!!

http://webapifinder.com/api/mostpopular
 

Jquery on Eclipse Juno

1) Install the plugin of following id JSDT jQuery Integration
(You can find it on Eclipse market places)
2)Go to Project Explorer--> JavaScript Resources

3)Right click on it and go to properties.

4)select "Add javascript library"

 

5)select "j Query Library"

6) You will get code completion as follows  

 

What is there behind Facebook?

 

1.Memcached

This is a distributed memory caching system which Facebook uses a caching layer between the web servers and MySQL servers.

2.HipHop for PHP
 Hip pop converts PHP (Server-side HTML embedded scripting language) into c++ code which can be then be compiled for better performance.And also PHP is used for the front-end.

3.Haystack
This is the Facebook's high performance photo storage/retrieval system.haystack is an object store.Facebook serves around 1.2 million photos per second.And each photo is saved in 4 different resolutions,resulting in more than 80 billion photos.

    4 .Cassandra

    Cassandra is a distributed storage system with no single pint of failure

    5.Scribe

    This is a flexible logging system that Facebook uses for many purposes internally.
  

   6.Erlang

   Used for the chat engine.