There are a couple of algorithms exists to reverse a singly linked list in Java e.g. You can use the three-pointers approach or solve this problem using a stack, or simply using recursion without the external stack. As I had pointed out on the earlier post about linked list, that reversing a linked list is one of the most popular data structure interview question, based on linked list, which means, you just can't afford to prepare this one, before going for any programming interview. Despite being so common, It's not easy to solve this problem on the fly. Many Java programmer struggles to reverse a linked list using both iteration and recursion, which makes this question very useful for filtering programmers who can code and who are not so good with coding. Indeed, this is one of the confusing algorithms to understand and it's not easy to grasp, especially if you haven't practiced linked list based questions e.g. finding middle node of linked list in one pass or inserting and removing an element from linked list data structure.
Scala is a programming language which aims to provide best of both object-oriented programming and functional programming world. It not only allows you to construct elegant class hierarchies for maximum code reuse and extensibility but also allows you to implement their behavior using higher-order functions and other functional programming technique. It is touted as one of the languages which can probably take over Java, though it didn't happen especially after Java 8 release which also provides some functional programming tools to Java e.g. lambda expression and stream. Nevertheless, Scala is a good language and created by following best practices from several other programming languages including Java. Scala is an acronym for “Scalable Language”. This means it is designed by keeping scalability in mind. Many companies e.g. Twitter, LinkedIn, and Intel uses it for their mission-critical application.
Today, we are going to see another common and interesting SQL interview question, what is the difference between SQL, T-SQL and PL/SQL? It is also one of the most common doubt among SQL beginners. It's common for programmers to think that why there are many types of SQL languages, why not just single SQL across DB? etc. Well, let's first understand the difference between SQL, T-SQL and PL/SQL and then we will understand the need of these dialects. SQL is standard for querying, inserting and modifying data in relational database. It is categorized into DDL and DML and powerful enough to create a database objects e.g. table, view, stored procedure and can perform CRUD operation (SELECT, INSERT, UPDATE, and DELETE) query.