J2SE Interview Questions and Answers 6

What is group ?
A collection of principals within a given security policy domain.

What is hierarchy ?
A classification of relationships in which each item except the top one (known as the root) is a specialized form of the item above it. Each item can have one or more items below it in the hierarchy. In the Java class hierarchy, the root is the Object class.

What is HTML ?
Hypertext Markup Language. This is a file format, based on SGML, for hypertext documents on the Internet. It is very simple and allows for the embedding of images, sounds, video streams, form fields and simple text formatting. References to other objects are embedded using URLs.

What is HTTP ?
Hypertext Transfer Protocol. The Internet protocol, based on TCP/IP, used to fetch hypertext objects from remote hosts. See also TCP/IP.

What is HTTPS ?
Hypertext Transfer Protocol layered over the SSL protocol.

What is IDL ?
Interface Definition Language. APIs written in the Java programming language that provide standards-based interoperability and connectivity with CORBA (Common Object Request Broker Architecture).

What is identifier ?
The name of an item in a program written in the Java programming language.

What is IIOP ?
Internet Inter-ORB Protocol. A protocol used for communication between CORBA object request brokers.

What is if ?
A Java keyword used to conduct a conditional test and execute a block of statements if the test evaluates to true.

What is impersonation ?
An act whereby one entity assumes the identity and privileges of another entity without restrictions and without any indication visible to the recipients of the impersonator's calls that delegation has taken place. Impersonation is a case of simple delegation.

What is implements ?
A Java keyword included in the class declaration to specify any interfaces that are implemented by the current class.

What is import ?
A Java keyword used at the beginning of a source file that can specify classes or entire packages to be referred to later without including their package names in the reference.

What is inheritance ?
The concept of classes automatically containing the variables and methods defined in their super types. See also super class, subclass.

What is instance ?
An object of a particular class. In programs written in the Java programming language, an instance of a class is created using the new operator followed by the class name.

What is instance method ?
Any method that is invoked with respect to an instance of a class. Also called simply a method. See also class method.

What is instance variable ?
Any item of data that is associated with a particular object. Each instance of a class has its own copy of the instance variables defined in the class. Also called a field. See also class variable.

What is instanceof ?
A two-argument Java keyword that tests whether the runtime type of its first argument is assignment compatible with its second argument.