J2SE Interview Questions and Answers 14

What is Technology Compatibility Kit (TCK) ?
A test suite, a set of tools, and other requirements used to certify an implementation of a particular Sun technology conformant both to the applicable specifications and to Sun or Sun-designated reference implementations.

What is thin client ?
A system that runs a very light operating system with no local system administration and executes applications delivered over the network.

What is 'this' ?
A Java keyword 'that' can be used to represent an instance of the class in which it appears. 'this' can be used to access class variables and methods.

What is thread ?
The basic unit of program execution. A process can have several threads running concurrently, each performing a different job, such as waiting for events or performing a time-consuming job that the program doesn't need to complete before going on. When a thread has finished its job, the thread is suspended or destroyed. See also process.

What is throw ?
A Java keyword that allows the user to throw an exception or any class that implements the "throwable" interface.

What is throws ?
A Java keyword used in method declarations that specify which exceptions are not handled within the method but rather passed to the next higher level of the program.

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 ?
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 transient ?
A keyword in the Java programming language that indicates that a field is not part of the serialized form of an object. When an object is serialized, the values of its transient fields are not included in the serial representation, while the values of its non-transient fields are included.

What is try ?
A Java keyword that defines a block of statements that may throw a Java language exception. If an exception is thrown, an optional catch block can handle specific exceptions thrown within the try block. Also, an optional finally block will be executed regardless of whether an exception is thrown or not.

What is type ?
A class or interface.

What is Unicode ?
A 16-bit character set defined by ISO 10646. See also ASCII. All source code in the Java programming environment is written in Unicode.

What is URI ?
Uniform Resource Identifier. A compact string of characters for identifying an abstract or physical resource. A URI is either a URL or a URN. URLs and URNs are concrete entities that actually exist; A URI is an abstract superclass.

What is URL ?
Uniform Resource Locator. A standard for writing a text reference to an arbitrary piece of data in the WWW. A URL looks like "protocol://host/localinfo" where protocol specifies a protocol to use to fetch the object (like HTTP or FTP), host specifies the Internet name of the host on which to find it, and localinfo is a string (often a file name) passed to the protocol handler on the remote host.