How to increase length of existing VARCHAR column in SQL Server

You can increase the length of a VARCHAR column without losing existing data in SQL Server. All you need to do is that execute following ALTER TABLE statements. Though, you need to specify NULL or NOT NULL constraint explicitly, depending upon your data.

Here is the SQL command you can use to increase the length of a VARCHAR column in SQL Server:

ALTER TABLE Books ALTER COLUMN title VARCHAR (432)

This command increases the length of title column of Books table to 432 characters. You can use the same command to increase the length of CHAR, NCHAR or NVARCHAR columns as well.

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How to find the first element of Stream in Java 8 - findFirst() Example

In Java 8, you can use the Stream.findFirst() method to get the first element of Stream in Java. This is a terminal operation and often used after applying several intermediate operations e.g. filter, mapping, flattening etc. For example, if you have a List of String and you want to find the first String whose length is greater than 10, you can use the findFirst() method along with stream() and filter() to get that String. The stream() method gets the Stream from a List, which then allow you to apply several useful methods defined in the java.util.Stream class e.g. filter(), map(), flatMap() etc.

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Java 1.5 Generics Tutorial: How Generics in Java works with Example of Collections, Best practices, Gotchas

Java Generics Tutorial

Generics in Java is one of important feature added in Java 5 along with Enum, autoboxing and varargs, to provide compile time type-safety. Generics is also considered to be one of the tough concepts to understand in Java and somewhat it’s true as well. I have read many articles on generics in Java, some of them are quite good and detailed but I still felt that those are either too much technical or exhaustively detailed, so I thought to write a simple yet informative article on Java generics to give a head start to beginners without bothering their head too much. In this Java generics tutorial, I will cover How Generics works in Java,  some mysterious wildcards in Generics and some important points about Generic in Java. I will try explaining generics concept in simple words and simple examples.

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Difference between Wait and Sleep, Yield in Java

The difference between wait and sleep or the difference between sleep and yield in Java are one of the popular core Java interview questions and asked on multi-threading interviews. Out of three methods which can be used to pause a thread in Java, sleep() and yield() methods are defined in thread class while wait() is defined in the Object class, which is another interview question. The key difference between wait() and sleep() is that former is used for inter-thread communication while later is used to introduced to pause the current thread for a short duration. This difference is more obvious from the fact that, when a thread calls the wait() method, it releases the monitor or lock it was holding on that object, but when a thread calls the sleep() method, it never releases the monitor even if it is holding. 

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Top 10 Servlet Interview Question Answers - J2EE

This time its servlet interview questions, I was thinking what to pick for my interview series and then I thought about J2EE and Servlet is my favorite on that space. Servlet is an important part of any J2EE development and serves as Controller on many web MVC frameworks and that’s why it’s quite popular on J2EE interviews. These Servlet questions are based on my experience as well as collected by friends and colleague and they are not only good for interview practice but also shows a new direction of learning for anyone who is not very familiar with servlet technology.

As said earlier this interview question article is part of my earlier series java interview questions , UNIX command interview questions and Java threading interview questions.

You can find answers to all these questions on google but I have also listed my answers for quick reference.

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Difference between Stack and Heap memory in Java

The difference between stack and heap memory is common programming question asked by beginners learning Java or any other programming language. Stack and heap memory are two terms programmers starts hearing once they started programming but without any clear and definite explanation. Lack of knowledge of what is a heap in Java and what is stack memory in Java results in misconceptions related to stack and heap. To add to this confusion, a stack is also a data structure which is used to store elements in LIFO(Last In First out) order and available in Java API as java.util.Stack. In general, both stack and heap are part of memory, a program is allocated and used for different purposes. Java program runs on JVM which is launched as a process by "java" command. Java also uses both stack and heap memory for different needs. In our last article 10 points on Java heap space, I have touched base on Java heap space and in this article we will see the difference between stack and heap memory in Java.

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How Garbage Collection works in Java

I have read many articles on Garbage Collection in Java, some of them are too complex to understand and some of them don’t contain enough information required to understand garbage collection in Java. Then I decided to write my own experience as an article. You can call it a tutorial about garbage collection in simple word, which would be easy to understand and have sufficient information to understand how garbage collection works in Java. Garbage collection works by employing several GC algorithm e.g. Mark and Sweep. There are different kinds of garbage collector available in Java to collect different area of heap memory e.g. you have serial, parallel and concurrent garbage collector in Java.

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