HashMap, TreeMap and LinkedHashMap all implements java.util.Map interface and following are their characteristics.HashMapHashMap has complexity of O(1) for insertion and lookup.HashMap allows one null key and multiple null values.HashMap does not maintain any order.TreeMapTreeMap has complexity of O(logN) for insertion and lookup.TreeMap does not allow null key but allow multiple ... Read More

Suppose if we are trying to add the numbers having non-numeric text between numbers of a string, then MySQL simply use the first number of that string to evaluate the addition along with a warning. Following example will exhibit this −Examplemysql> Select '1525 * 2' + '200'As Total; +-------+ | ... Read More

MySQL have two functions namely LPAD() and RPAD() with the help of which we can stuff a string with another string.LPAD() function, as the name suggests, left stuff a string with another string. Following is the syntax for using it in MySQL −SyntaxLPAD(original_string, @length, pad_string)Here,  original_string is the string in ... Read More

When we use MySQL ORDER BY clause with RAND() function then the result set would have the shuffled set of rows. In other words, the result set would be in a random order. To understand it considers a table ‘Employee’ having the following records −mysql> Select * from employee; +----+--------+--------+ ... Read More

We need to use COUNT(*) function with SELECT clause to count the total number of rows in a table.Examplemysql> Select COUNT(*) from Student; +----------+ | COUNT(*) | +----------+ | 4        | +----------+ 1 row in set (0.06 sec)The query above counts the total number of ... Read More

As we know that a PRIMARY KEY column must have unique values and cannot have null values hence if we will define a column with UNIQUE and NOT NULL constraint both then that column would become PRIMARY KEY column.ExampleIn this example, we have created a table ‘Student123’ by defining column ... Read More

To get the Natural logarithm of 2, use the Math.LN2 property in JavaScript. It returns the natural logarithm of 2, which is approximately 0.693.ExampleYou can try to run the following code to get Natural logarithm of 2 −Live Demo           JavaScript Math LN2 Property     ... Read More

The Internet has become a very important part of our daily lives and has its applications in wide areas.Some of the areas in which Internet is used are −CommunicationsEducation and researchInstant messagingOnline business and shoppingOnline financial servicesFile and data sharingDeveloping collaborative softwareDesign and development of applications and computing environmentsContent managementEntertainmentSocial ... Read More

The application layer is the highest abstraction layer of the TCP/IP model that provides the interfaces and protocols needed by the users. It combines the functionalities of the session layer, the presentation layer and the application layer of the OSI model.The functions of the application layer are −It facilitates the user ... Read More

The presentation layer (Layer 6) ensures that the message is presented to the upper layer in a standardized format. It deals with the syntax and the semantics of the messages.The main functions of the presentation layer are as follows −It encodes the messages from the user dependent format to the ... Read More