Technology Questions

The wait(), notify(), and notifyAll() methods are used to provide an efficient way for threads to wait for a shared resource. When a thread executes an object's wait() method, it enters the waiting state. It only enters the ready state after another thread invokes the object's notify() or notifyAll() methods..

We need to first login to the data base as: SQLPLUS followed by user_name/password. Then we need to execute the following query:

CREATE USER user_name IDENTIFIED BY abcd; in this query a user_name suggest the user that is created which has a password abcd which is required for login in database.

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

Session storage is same like local storage but the data is valid for a session. In simple words the data is deleted as soon as you close the browser.

To create a session storage you need to use “sessionStorage.variablename” . In the below code we have a created a variable called as “clickcount”.

If you refresh the browser the count increases. But if you close the browser and start again the “clickcount” variable starts from zero.

if(sessionStorage.clickcount)

{

sessionStorage.clickcount=Number(sessionStorage.clickcount)+1;

}

else

{

sessionStorage.clickcount = 0;

} 

- The Set interface provides methods for accessing the elements of a finite mathematical set

- Sets do not allow duplicate elements

- Contains no methods other than those inherited from Collection

- It adds the restriction that duplicate elements are prohibited

- Two Set objects are equal if they contain the same elements

We can use the following method call:

boolean createNewFile();

This method creates a new file on the HD. 

If a file is already existing with the name given in the constructor then this method does not creates file on HD.

If file is successfully created then this method returns true.

If file is already existing on the HD then this method returns false.

This method may throw IOException whenever IO error is generated while creating file on HD.

Pass By Reference means the passing the address itself rather than passing the value. Passby Value means passing a copy of the value to be passed.