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An array is a group of similar typed variables that are referred to by a common name. Arrays of any type can be created and may have one or more dimensions. more...
Each of Java's eight primitive data types has a class dedicated to it. These are known as wrapper classes, because they "wrap" the primitive data type into an object of that class. more...
One of the advantages of Object-Oriented programming language is code reuse. There are two ways we can do code reuse either by implementation of inheritance (IS-A relationship), or object composition (HAS-A relationship). more...
One of the advantages of Object-Oriented programming language is code reuse. There are two ways we can do code reuse either by implementation of inheritance (IS-A relationship), or object composition (HAS-A relationship). more...
One of the advantages of Object-Oriented programming language is code reuse. There are two ways we can do code reuse either by implementation of inheritance (IS-A relationship), or object composition (HAS-A relationship). more...
Not everything in Java is an object. There is a special group of data types (also known as primitive types) that will be used quite often in programming. For performance reasons, the designers of the Java language decided to include these primitive types. Java determines the size of each primitive type. more...
While working with JSON, often you may need a JSON viewer. This document discusses several online JSON viewer. Hopefully, this will help you to select one depending upon your requirement. more...
This tutorial will help you to understand about Java OOP’S concepts with examples. Let’s discuss about what are the features of Object Oriented Programming. more...
A decently size project can have hundreds of Java classes and you need to organize them in packages (think file directories). more...
All computer programs consist of two elements: code and data. Furthermore, a program can be conceptually organized around its code or around its data. more...
Featured tutorials
MySQL tutorial of w3resource is a comprehensive tutorial to learn MySQL. We have hundreds of examples covered, often with PHP code. This helps you to learn how to create PHP-MySQL based web applications. more...
Learn one of the most widely used and advanced open source database system with w3resource. more...
SQL tutorial of w3resource is a comprehensive tutorial to learn SQL. We have followed SQL:2003 standard of ANSI. There are hundreds of examples given in this tutorial. Output are shown with Oracle 10G. Often outputs are followed by pictorial presentation and explanation for better understanding. more...
$_SERVER is an array which holds information of headers, paths, script locations. Web server creates the entries in the array. more...
MySQL INSERT INTO statement is used to insert record(s) or row(s) into a table. The insertion of records or rows in the table can be done in two ways. Insert a single row at a time, and inserting multiple rows at a time.more...
A SELF JOIN is another type of join in sql which is used to join a table to itself, specially when the table has a FOREIGN KEY which references its own PRIMARY KEY. more...
The PHP for loop allows the user to put all the loop-related statements (i.e. INITIALIZER; CONDITION; INCREMENTOR or DECREMENTOR) in one place. The structure is similar to C language. more...
w3resource.com has a comprehensive SQL Tutorial and we have covered SQL JOIN in great detail. But we felt that creating a cheat sheet on SQL JOIN will be very useful for you. more...
For client side form validation, using JavaScript is inevitable. But not any more. With HTML5, now you may validate your forms at client side without using any JavaScript. more...
MySQL COUNT() function returns a count of number of non-NULL values of a given expression. If it does not find any matching row, it returns 0. more...