J2SE Interview Questions and Answers 13

What is SGML ?
Standardized Generalized Markup Language. An ISO/ANSI/ECMA standard that specifies a way to annotate text documents with information about types of sections of a document.

What is SOAP ?
The Simple Object Access Protocol (SOAP) uses a combination of XML-based data structuring and the Hyper Text Transfer Protocol (HTTP) to define a standardized method for invoking methods in objects distributed in diverse operating environments across the Internet.

What is SQL ?
Structured Query Language. The standardized relational database language for defining database objects and manipulating data.

What is static ?
A Java keyword used to define a variable as a class variable. Classes maintain one copy of class variables regardless of how many instances exist of that class. static can also be used to define a method as a class method. Class methods are invoked by the class instead of a specific instance, and can only operate on class variables.

What is static field ?
Another name for class variable.

What is static method ?
Another name for class method.

What is stream ?
A stream is simply a byte-stream of data that is sent from a sender to a receiver. There are two basic categories, so the java.io package includes two abstract classes (InputStream and OutputStream).

What is subclass ?
A class that is derived from a particular class, perhaps with one or more classes in between. See also superclass, supertype.

What is subtype ?
If type X extends or implements type Y, then X is a subtype of Y. See also supertype.

What is superclass ?
A class from which a particular class is derived, perhaps with one or more classes in between. See also subclass, subtype.

What is super ?
A Java keyword used to access members of a class inherited by the class in which it appears.

What is supertype ?
The supertypes of a type are all the interfaces and classes that are extended or implemented by that type. See also subtype, superclass.

What is switch ?
A Java keyword used to evaluate a variable that can later be matched with a value specified by the case keyword in order to execute a group of statements.

What is Swing ?
A collection of graphical user interface (GUI) components that runs uniformly on any native platform which supports the Java virtual machine*. Because they are written entirely in the Java programming language, these components may provide functionality above and beyond that provided by native-platform equivalents. (Contrast with AWT.)

What is synchronized ?
A keyword in the Java programming language that, when applied to a method or code block, guarantees that at most one thread at a time executes that code.

What is TCP/IP ?
Transmission Control Protocol based on IP. This is an Internet protocol that provides for the reliable delivery of streams of data from one host to another.