Languages-Java [3i Infotech Placement]: Sample Questions 127 - 129 of 141

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Question 127

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Write in Short

Short Answer▾

Which class begins Java class hierarchy?

Explanation

Declare Java Class Hierarchy
  • Object class begins java class hierarchy.
  • Defines java. lang package- defines and implements behaviour common to all classes.
  • Its methods are available to all java classes.
  • Acts as a root of inheritance hierarchy in any java program.

Question 128

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Short Answer▾

What is meant by session? Explain something about HTTP Session class?

Explanation

  • A session includes all requests that a client makes to a server in a specific time.
  • A session is user specific and for each user a new session tracks the requests from that user.
  • A separate session variable on server is associated with each session.

HTTP Session Class

Http Session is an interface that identifies a user across more that one page request and stores state about that user across pages.

Question 129

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Describe in Detail

Essay▾

Have you ever used Hash table and directory?

Explanation

Hash Table

  • Yes, we have ever used hash table in java.
  • It is an implementation of the key value pair of the data structure in the java.
  • Offers similar performance as arrays with numerical indices, but flexible in terms of key.

Directory

  • The concept of a directory in java can be accomplished using the file class.
  • This class provide listFile method whihc returns list File object for directory.
  • Represents file or subdirectories.

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