J2EE Interview Questions and Answers 19

What is tool provider ?
An organization or software vendor that provides tools used for the development, packaging, and deployment of J2EE applications.

What is transaction attribute ?
A value specified in an enterprise bean's deployment descriptor that is used by the EJB container to control the transaction scope when the enterprise bean's methods are invoked. A transaction attribute can have the following values: Required, RequiresNew, Supports, NotSupported, Mandatory, or Never.

What is transaction ?
An atomic unit of work that modifies data. A transaction encloses one or more program statements, all of which either complete or roll back. Transactions enable multiple users to access the same data concurrently.

What is transaction isolation level ?
What is transaction isolation level The degree to which the intermediate state of the data being modified by a transaction is visible to other concurrent transactions and data being modified by other transactions is visible to it.

What is transaction manager ?
Provides the services and management functions required to support transaction demarcation, transactional resource management, synchronization, and transaction context propagation.

What is Unicode ?
A standard defined by the Unicode Consortium that uses a 16-bit code page that maps digits to characters in languages around the world. Because 16 bits covers 32,768 codes, Unicode is large enough to include all the world's languages, with the exception of ideographic languages that have a different character for every concept, such as Chinese.

What is Universal Description, Discovery and Integration (UDDI) project ?
An industry initiative to create a platform-independent, open framework for describing services, discovering businesses, and integrating business services using the Internet, as well as a registry. It is being developed by a vendor consortium.

What is Universal Standard Products and Services Classification (UNSPSC) ?
A schema that classifies and identifies commodities. It is used in sell-side and buy-side catalogs and as a standardized account code in analyzing expenditure.

What is unparsed entity ?
A general entity that contains something other than XML. By its nature, an unparsed entity contains binary data.

What is URI ?
Uniform resource identifier. A globally unique identifier for an abstract or physical resource. A URL is a kind of URI that specifies the retrieval protocol (http or https for Web applications) and physical location of a resource (host name and host-relative path). A URN is another type of URI.

What is URL ?
Uniform resource locator. A standard for writing a textual reference to an arbitrary piece of data in the World Wide Web. A URL looks like this: protocol://host/local info where protocol specifies a protocol for fetching the object (such as http or ftp), host specifies the Internet name of the targeted host, and local info is a string (often a file name) passed to the protocol handler on the remote host.

What is URL path ?
The part of a URL passed by an HTTP request to invoke a servlet. A URL path consists of the context path + servlet path + path info, where Context path is the path prefix associated with a servlet context of which the servlet is a part. If this context is the default context rooted at the base of the Web server's URL namespace, the path prefix will be an empty string. Otherwise, the path prefix starts with a / character but does not end with a / character. Servlet path is the path section that directly corresponds to the mapping that activated this request. This path starts with a / character. Path info is the part of the request path that is not part of the context path or the servlet path

What is URN ?
Uniform resource name. A unique identifier that identifies an entity but doesn't tell where it is located. A system can use a URN to look up an entity locally before trying to find it on the Web. It also allows the Web location to change, while still allowing the entity to be found.

What is user data constraint ?
Indicates how data between a client and a Web container should be protected. The protection can be the prevention of tampering with the data or prevention of eavesdropping on the data.