J2SE Interview Questions and Answers 12

What is RMI ?
See Java Remote Method Invocation.

What is rollback ?
The point in a transaction when all updates to any databases involved in the transaction are reversed.

What is root ?
In a hierarchy of items, the one item from which all other items are descended. The root item has nothing above it in the hierarchy. See also hierarchy, class, package.

What is RPC ?
Remote Procedure Call. Executing what looks like a normal procedure call (or method invocation) by sending network packets to some remote host.

What is runtime system ?
The software environment in which programs compiled for the Java virtual machine1 can run. The runtime system includes all the code necessary to load programs written in the Java programming language, dynamically link native methods, manage memory, handle exceptions, and an implementation of the Java virtual machine, which may be a Java interpreter.

What is SAX ?
Simple API for XML. An event-driven, serial-access mechanism for accessing XML documents.

What is sandbox ?
Comprises a number of cooperating system components, ranging from security managers that execute as part of the application, to security measures designed into the Java virtual machine1 and the language itself. The sandbox ensures that an untrusted, and possibly malicious, application cannot gain access to system resources.

What is scope ?
A characteristic of an identifier that determines where the identifier can be used. Most identifiers in the Java programming environment have either class or local scope. Instance and class variables and methods have class scope; they can be used outside the class and its subclasses only by prefixing them with an instance of the class or (for class variables and methods) with the class name. All other variables are declared within methods and have local scope; they can be used only within the enclosing block.

What is Secure Socket Layer (SSL) ?
A protocol that allows communication between a Web browser and a server to be encrypted for privacy.

What is security attributes ?
A set of properties associated with a principal. Security attributes can be associated with a principal by an authentication protocol.

What is security context ?
An object that encapsulates the shared state information regarding security between two entities.

What is security policy domain ?
A scope over which security policies are defined and enforced by a security administrator. A security policy domain has the following characteristics:
It has a collection of users (or principals).
It uses a well defined authentication protocol(s) for authenticating users (or principals).
It may have groups to simplify setting of security policies.

What is security technology domain ?
A scope over which the same security mechanism is used to enforce a security policy. Multiple security policy domains can exist within a single technology domain.

What is serialization ?
The encoding of objects, and the objects reachable from them, into a stream of bytes and the complementary reconstruction of the object graph from the stream.

What is short ?
A Java keyword used to define a variable of type short.

What is single precision ?
In the Java language specification, describes a floating point number with 32 bits of data. See also double precision.