Java J2EE Interview Questions and Answers for Freshers - 4

Question: 16

What is resource manager?

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

Question: 17

What is RAR?

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

Question: 18

What are the differences between Ear, Jar, and War files?

Jar files (files with a .jar extension) are intended to hold generic libraries of Java classes, resources, auxiliary files, etc.

War files (files with a .war extension) are intended to contain complete Web applications. In this context, a Web application is defined as a single group of files, classes, resources, .jar files that can be packaged and accessed  as one servlet context.

Ear files (files with a .ear extension) are intended to contain complete enterprise applications. In this context, an enterprise application is defined as a collection of .jar files, resources, classes, and multiple Web applications.

Each type of file (.jar,.ear,.war) is processed uniquely by application servers, servlet containers,

EJB containers etc.

Question: 19

What is distributed application?

An application made up of distinct components running in separate runtime environments, usually on different platforms connected via a network.

Typical distributed applications are two tier (client-server), three tier (client-middleware-server), and multitier (client-multiple middleware-multiple servers).

Question: 20

What is tag?

In XML documents, a piece of text that describes a unit of data or an element. The tag is distinguishable as markup, as opposed to data, because it is surrounded by angle brackets (< and >). To treat such markup syntax as data, you use an entity reference or a CDATA section.