Question 1

How to create Directory on the HD?

Accepted Answer

To create directory on the HD we use mkDir() method: boolean mkDir(); This method returns true if the directory is created on HD This method returns false if the directory is already existing on HD

Question 2

How to check that the file object is pointing a file on HD?

Accepted Answer

boolean isFile();

Question 3

How to check that whether the file object is pointing a folder or not?

Accepted Answer

boolean isDirectory();

Question 4

How to get last modified date of a file?

Accepted Answer

long lastModified(); we can give this return value to a date object and we can get data to be displayed

Question 5

How to get contents of the folder?

Accepted Answer

File[] listFiles(); this method returns list of files stored in a directory

Question 6

What is Thread?

Accepted Answer

A Thread is a block of code that can be executed in parallel with another block of code

Question 7

What is MultiTasking?

Accepted Answer

Executing more than one program simultaniously(ie at time) Ex: Windows media player is a program Internet explorer(IE) is another program executing both the programs at a time is called multi tasking

Question 8

What is MultiThreading?

Accepted Answer

Executing two or more blocks (threads) of a program at a time is called MultiThreading

Question 9

How to do MultiThreading in Java?

Accepted Answer

To do multi threading in java we use interfaces and classes defined in javalang package Those classes and interfaces are: JavalangRunnable, Javalang Thread, JavalangThreadGroup

Question 10

Why synchronization?

Accepted Answer

When ever two or more threads are sharing same data for updating then unpredicted result will be there in the data For Example take a thread is depositing amount in Account Object and another thread is withdrawing amount from the same Account Object when ever both threads are executed simultaneously then unexpected result is stored in the balance of the Account Object

Question 11

When finally block is executed?

Accepted Answer

If exception is generated in try and if that exception is not catch by any catch then finally is executed If exception is generated in try and if that exception is caught by one of catch statements then also finally is executed if no exception is generated then also finally is executed

Question 12

How to call a constructor in java?

Accepted Answer

Constructor chaining is the process of calling one constructor from another constructor with respect to current object Within same class: It can be done using this() keyword for constructors in same class From base class: by using super() keyword to call constructor from the base class

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