J2EE Interview Questions with Answers Page IV

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What is OASIS?

Organization for the Advancement of Structured Information Standards. A consortium that drives the development, convergence, and adoption of e-business

standards.

What is OMG?

Object Management Group. A consortium that produces and maintains computer industry specifications for interoperable enterprise applications.

What is one-way messaging?

A method of transmitting messages without having to block until a response is received.

What is ORB?

Object request broker. A library that enables CORBA objects to locate and communicate with one another.

What is OS principal?

A principal native to the operating system on which the J2EE platform is executing.

What is OTS?

Object Transaction Service. A definition of the interfaces that permit CORBA objects to participate in transactions.

What is parameter entity?

An entity that consists of DTD specifications, as distinct from a general entity. A parameter entity defined in the DTD can then be referenced at other

points, thereby eliminating the need to recode the definition at each location it is used.

What is parsed entity?

A general entity that contains XML and therefore is parsed when inserted into the XML document, as opposed to an unparsed entity.

What is parser?

A module that reads in XML data from an input source and breaks it into chunks so that your program knows when it is working with a tag, an attribute,

or element data. A nonvalidating parser ensures that the XML data is well formed but does not verify that it is valid. See also validating parser.

What is passivation?

The process of transferring an enterprise bean from memory to secondary storage. See activation.

What is persistence?

The protocol for transferring the state of an entity bean between its instance variables and an underlying database.

What is persistent field?

A virtual field of an entity bean that has container-managed persistence; it is stored in a database.

What is prolog?

The part of an XML document that precedes the XML data. The prolog includes the declaration and an optional DTD.

What is POA?

Portable Object Adapter. A CORBA standard for building server-side applications that are portable across heterogeneous ORBs.

What is point-to-point messaging system?

A messaging system built on the concept of message queues. Each message is addressed to a specific queue; clients extract messages from the queues

established to hold their messages.

What is programmatic security?

Security decisions that are made by security-aware applications. Programmatic security is useful when declarative security alone is not sufficient to

express the security model of an application.

What is primary key?

An object that uniquely identifies an entity bean within a home.

What is processing instruction?

Information contained in an XML structure that is intended to be interpreted by a specific application.

What is principal?

The identity assigned to a user as a result of authentication.

What is privilege?

A security attribute that does not have the property of uniqueness and that can be shared by many principals.

What is publish/subscribe messaging system?

A messaging system in which clients address messages to a specific node in a content hierarchy, called a topic. Publishers and subscribers are

generally anonymous and can dynamically publish or subscribe to the content hierarchy. The system takes care of distributing the messages arriving from

a node's multiple publishers to its multiple subscribers.

What is public key certificate?

Used in client-certificate authentication to enable the server, and optionally the client, to authenticate each other. The public key certificate is

the digital equivalent of a passport. It is issued by a trusted organization, called a certificate authority, and provides identification for the

bearer.

What is query string?

A component of an HTTP request URL that contains a set of parameters and values that affect the handling of the request.

What is RAR?

Resource Adapter Archive. A JAR archive that contains a resource adapter module.

What is RDF?

Resource Description Framework. A standard for defining the kind of data that an XML file contains. Such information can help ensure semantic

integrity-for example-by helping to make sure that a date is treated as a date rather than simply as text.

What is RDF schema?

A standard for specifying consistency rules that apply to the specifications contained in an RDF.

What is realm?

See security policy domain. Also, a string, passed as part of an HTTP request during basic authentication, that defines a protection space. The

protected resources on a server can be partitioned into a set of protection spaces, each with its own authentication scheme or authorization database

or both. In the J2EE server authentication service, a realm is a complete database of roles, users, and groups that identify valid users of a Web

application or a set of Web applications.

What is reentrant entity bean?

An entity bean that can handle multiple simultaneous, interleaved, or nested invocations that will not interfere with each other.

What is reference?

A reference to an entity that is substituted for the reference when the XML document is parsed. It can reference a predefined entity such as < or

reference one that is defined in the DTD. In the XML data, the reference could be to an entity that is defined in the local subset of the DTD or to an

external XML file (an external entity). The DTD can also carve out a segment of DTD specifications and give it a name so that it can be reused

(included) at multiple points in the DTD by defining a parameter entity.

What is registry provider?

An implementation of a business registry that conforms to a specification for XML registries (for example, ebXML or UDDI).

What is relationship field?

A virtual field of an entity bean having container-managed persistence; it identifies a related entity bean.

What is remote interface?

One of two interfaces for an enterprise bean. The remote interface defines the business methods callable by a client.

What is remove method?

Method defined in the home interface and invoked by a client to destroy an enterprise bean.

What is renderer?

A Java class that can render the output for a set of JavaServer Faces UI components.

What is render kit?

A set of renderers that render output to a particular client. The JavaServer Faces implementation provides a standard HTML render kit, which is

composed of renderers that can render HMTL markup.

What is request-response messaging?

A method of messaging that includes blocking until a response is received.

What is resource adapter?

A system-level software driver that is used by an EJB container or an application client to connect to an enterprise information system. A resource

adapter typically is specific to an enterprise information system. It is available as a library and is used within the address space of the server or

client using it. A resource adapter plugs in to a container. The application components deployed on the container then use the client API (exposed by

the adapter) or tool-generated high-level abstractions to access the underlying enterprise information system. The resource adapter and EJB container

collaborate to provide the underlying mechanisms-transactions, security, and connection pooling-for connectivity to the enterprise information system.

What is resource adapter module?

A deployable unit that contains all Java interfaces, classes, and native libraries, implementing a resource adapter along with the resource adapter

deployment descriptor.

What is resource manager?

Provides access to a set of shared resources. A resource manager participates in transactions that are externally controlled and coordinated by a

transaction manager. A resource manager typically is in a different address space or on a different machine from the clients that access it. Note: An

enterprise information system is referred to as a resource manager when it is mentioned in the context of resource and transaction management.

What is resource manager connection?

An object that represents a session with a resource manager.

What is resource manager connection factory?

An object used for creating a resource manager connection.

What is RMI?

Remote Method Invocation. A technology that allows an object running in one Java virtual machine to invoke methods on an object running in a different

Java virtual machine.

What is RMI-IIOP?

A version of RMI implemented to use the CORBA IIOP protocol. RMI over IIOP provides interoperability with CORBA objects implemented in any language if

all the remote interfaces are originally defined as RMI interfaces.

What is role (development)?

The function performed by a party in the development and deployment phases of an application developed using J2EE technology. The roles are application

component provider, application assembler, deployer, J2EE product provider, EJB container provider, EJB server provider, Web container provider, Web

server provider, tool provider, and system administrator.

What is role mapping?

The process of associating the groups or principals (or both), recognized by the container with security roles specified in the deployment descriptor.

Security roles must be mapped by the deployer before a component is installed in the server.

What is role (security)?

An abstract logical grouping of users that is defined by the application assembler. When an application is deployed, the roles are mapped to security

identities, such as principals or groups, in the operational environment. In the J2EE server authentication service, a role is an abstract name for

permission to access a particular set of resources. A role can be compared to a key that can open a lock. Many people might have a copy of the key; the

lock doesn't care who you are, only that you have the right key.

What is rollback?

The point in a transaction when all updates to any resources involved in the transaction are reversed.

What is root?

The outermost element in an XML document. The element that contains all other elements.

What is SAX?

Abbreviation of Simple API for XML.

What is Simple API for XML?

An event-driven interface in which the parser invokes one of several methods supplied by the caller when a parsing event occurs. Events include

recognizing an XML tag, finding an error, encountering a reference to an external entity, or processing a DTD specification.

What is schema?

A database-inspired method for specifying constraints on XML documents using an XML-based language. Schemas address deficiencies in DTDs, such as the

inability to put constraints on the kinds of data that can occur in a particular field. Because schemas are founded on XML, they are hierarchical. Thus

it is easier to create an unambiguous specification, and it is possible to determine the scope over which a comment is meant to apply.

What is Secure Socket Layer (SSL)?

A technology that allows Web browsers and Web servers to communicate over a secured connection.

What is security attributes?

A set of properties associated with a principal. Security attributes can be associated with a principal by an authentication protocol or by a J2EE

product provider or both.

What is security constraint?

A declarative way to annotate the intended protection of Web content. A security constraint consists of a Web resource collection, an authorization

constraint, and a user data constraint.

What is security context?

An object that encapsulates the shared state information regarding security between two entities.

What is security permission?

A mechanism defined by J2SE, and used by the J2EE platform to express the programming restrictions imposed on application component developers.

What is security permission set?

The minimum set of security permissions that a J2EE product provider must provide for the execution of each component type.

What is security policy domain?

A scope over which security policies are defined and enforced by a security administrator. A security policy domain has a collection of users (or

principals), uses a well-defined authentication protocol or protocols for authenticating users (or principals), and may have groups to simplify setting

of security policies.