Talking about Java, almost all programmers knows that. That's why this is one of the popular weed out questions on programming interviews. If a Java programmer doesn't know difference between static and non-static method, he is probably not ready yet, and needs more practice and experience. With half knowledge, making a method static can have serious repercussionespecially in today's heavily multi-threaded Java application.
The body of this message is typically the requested resource, although an error message or other information may also be returned. HTTP provides a general framework for access control and authentication, via an extensible set of challenge-response authentication schemes, which can be used by a server to challenge a client request and by a client to provide authentication information.
The realm value string, if present, is combined with the canonical root URI to form the protection space component of the challenge.
This in effect allows the server to define separate authentication scopes under one root URI. The request message, response header section, and response body are highlighted. What this resource represents, whether pre-existing data or data that is generated dynamically, depends on the implementation of the server.
Often, the resource corresponds to a file or the output of an executable residing on the server. By being specified in these documents, their semantics are well known and can be depended on.
Any client can use any method and the server can be configured to support any combination of methods. If a method is unknown to an intermediate, it will be treated as an unsafe and non-idempotent method.
There is no limit to the number of methods that can be defined and this allows for future methods to be specified without breaking existing infrastructure. Requests using GET should only retrieve data and should have no other effect.
This is also true of some other HTTP methods. This is useful for retrieving meta-information written in response headers, without having to transport the entire content. The data POSTed might be, for example, an annotation for existing resources; a message for a bulletin board, newsgroup, mailing list, or comment thread; a block of data that is the result of submitting a web form to a data-handling process; or an item to add to a database.
If the URI refers to an already existing resource, it is modified; if the URI does not point to an existing resource, then the server can create the resource with that URI. In other words, they should not have side effectsbeyond relatively harmless effects such as loggingcachingthe serving of banner advertisements or incrementing a web counter.
However, this is not mandated by the standard, and it is explicitly acknowledged that it cannot be guaranteed.
Such methods are therefore not usually used by conforming web robots or web crawlers ; some that do not conform tend to make requests without regard to context or consequences.
Despite the prescribed safety of GET requests, in practice their handling by the server is not technically limited in any way. Therefore, careless or deliberate programming can cause non-trivial changes on the server.
This is discouraged, because it can cause problems for web cachingsearch engines and other automated agents, which can make unintended changes on the server. For example, a website might allow deletion of a resource through a URL such as http: The beta was suspended only weeks after its first release, following widespread criticism.
In some cases this may be desirable, but in other cases this could be due to an accident, such as when a user does not realize that their action will result in sending another request, or they did not receive adequate feedback that their first request was successful.
While web browsers may show alert dialog boxes to warn users in some cases where reloading a page may re-submit a POST request, it is generally up to the web application to handle cases where a POST request should not be submitted more than once.
Note that whether a method is idempotent is not enforced by the protocol or web server. It is perfectly possible to write a web application in which for example a database insert or other non-idempotent action is triggered by a GET or other request.
Security[ edit ] The TRACE method can be used as part of a class of attacks known as cross-site tracing ; for that reason, common security advice is for it to be disabled in the server configuration.Classes and Objects are basic concepts of Object Oriented Programming which revolve around the real life entities.
Class. A class is a user defined blueprint or prototype from which objects are created. Perform create, read, update, and delete operations (CRUD) DynamoDB items using the AWS SDK for Java. How is it possible to read/write to the Windows registry using Java?
A race condition is a situation in which two or more threads or processes are reading or writing some shared data, and the final result depends on the timing of how the threads are scheduled.
Java Write to File. 4 different ways to write file in java. We can use FileWriter, BufferedWriter, Java 7 Files class and FileOutputStream. Java i About the Tutorial Java is a high-level programming language originally developed by Sun Microsystems and released in Java runs on a variety of .