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Since 1998, DevX has helped people start businesses, build websites, and provide enterprise technology to people globally. Interviewing the likes of Microsoft’s co-founder, Steve Ballmer, the publication brings comprehensive, reliable, and accessible insights to the Internet.
Serverless computing is a cloud computing model in which the main characteristic is that the user does not have to rent any virtual machines at all???the entire process of starting
The assert macro will terminate the program, often with a message about the assert statement, if its argument are false. #include #include int main(){int x = 10;int y = 2;assert(x==y);}
Did you know that SQL has built-in JSON functions? These can come in very handy! Instead of creating a very complicated query that exports XML and then translate it to
The Webbrowser control provides us with the “ProgressChanged” event. We can use the “CurrentProgress” and “MaximumProgress” Properties of the WEbBrowserProgressChangedEventArgs in this method to determine the percentage of the page
To allow your query methods to be transactional, you should use @Transactional at the repository interface that you define. For reading operations, the transaction configuration readOnly flag should be set
If you need to find the source code for a function or procedure in the database, it’s easy to do in Oracle. You can query the all_source view to get
The Cloud, micro-services and distributed systems are all the rage these days. But, in the end, each service and software component is implemented in some programming language. In the olden
There is a lot of similarities between detective stories (from Sherlock Holmes, James Bond,???) and troubleshooting production problems. Detective stories need to have a very complex/burning problem. If your application is experiencing issues in production, it automatically becomes a burning problem in the enterprise and gets attention from Senior Management. A detective uses very basic clues, extrapolates them, rules out the odd possibilities, puts a lot of hard work and identifies the villain. He fights against all odds, takes risks and eradicates the evil. A lot of heroism is involved. This is no way different from debugging/troubleshooting complex production problems. Thus I am going to introduce a fictional troubleshooting character: ???Jack Che???. Through this fictional character ??? I am going to narrate how complex real world production problems faced by major enterprises are solved. Feel free to share your comments and let me know whether you like it. If not I can always revert back to regular writing style. While twitter, Google and others are talking about 10 milliseconds, 20 milliseconds response time, still there are significant enterprises whose response time runs for several seconds. There is one such enterprise, whose response time was running for several seconds for their ???search??? transactions. Recently, this enterprise ported their application to AWS Elastic Beanstalk environment in Java 8/Tomcat 8. When a customer performs ???search??? operation on this application, a progress bar is displayed on the browser. Once search completes, progress bar vanishes and search results are displayed. After porting to AWS Elastic Beanstalk for certain data conditions, the customer was seeing a progress bar on the screen forever. Management didn???t know what was causing this issue and how to go about solving it. Thus they engaged Tier1app LLC to solve the problem. Tier1app LLC sent out their top notch troubleshooting detective ???Jack Che??? to solve the problem. HTTP 504 Gateway Time-out Error Code Just like every time, Jack Che was super excited to solve this problem. He assessed the situation quickly. He wanted to understand what interaction was going on between the Server and the browser. Thus he launched the developer console in the chrome browser and triggered the search transaction. A few seconds later, he saw HTTP 504 error code thrown from the server. (HTTP 504 is a time-out error thrown from the backend). Ah, he got his first clue. Now Jack Che started to review the Ajax javascript which made the backend server side call. Unfortunately, javascript didn???t have any error handling code in place. Thus, when error code was thrown it wasn???t handled and the screen was displaying progress bar forever. Wow, initial breakthrough for Jack Che within few minutes of his job. Seeing the smoke, where is the fire? Now Jack Che was curious to figure out from where this HTTP 504 error code is thrown? Jack Che found a second clue now; exactly at 60th second of the search transaction, this HTTP 504 error code was thrown. Since exactly at 60th second, HTTP 504 error code was thrown, Jack Che believed there is some sort of timeout is kicking in. But he wasn???t sure where this timeout value is configured. He searched all throughout the application source code to see whether any 60 seconds timeout is configured. He checked with the application development team. But there was no 60 seconds timeout configured anywhere within the application source code. Elastic Beanstalk Architecture Now he came to the conclusion that timeout is triggered by some component that is outside of the source code. Thus he started to examine each layer in the technology stack. Below is a very quick overview of the Elastic Beanstalk architecture.
Spring provides a nice abstraction on top of the JDBC API using JdbcTemplate and also provides great transaction management capabilities using annotation-based approach. By using the JdbcTemplate and NamedParameterjdbcTemplate classes,
You may not know this, but you can have an optional Parameter in SQL. It took me forever to figure it out. In any case, you can implement an optional
You may not know this but you can have optional Parameters in SQL. It took me forever to figure it out. In any case, you can implement an optional parameter
Aspect Oriented Programming (AOP) has been around for a long time now. It enables you to decouple the cross cutting concerns from your application and solve code tangling and eliminate
There are situations when we need to understand the time taken for executing a section of code. We are also aware that System.currentTimeMillis() provides a good estimate of time. System.nanoTime()
The system variables are exposed through the GetEnvironmentVariables method in the System.Environment class. var environmentVariables = System.Environment.GetEnvironmentVariables();foreach (var ev in environmentVariables){ DictionaryEntry de = (DictionaryEntry) ev; Console.WriteLine(string.Format(“Key: {0}, Value: {1}”,
It is a good idea to use @RestController (instead of simply @Controller), because it ensures you that it will return a Java Object rather than a reference to an HTML
Unlike Visual Basic, C# doesn’t have built-in string methods to extract parts of string from the Left, Right or a location specified through Mid. Unfortunately you have to create the
Managing large clusters of machines is non-trivial. Even in the cloud where the cloud provider takes care of a lot of the complicated stuff, such as networking, isolation and redundancy,
The PROPER function in Excel allows us to convert text to the right case in a quick way. You would have to use the Proper function with the cell address.
The following class describes a method that can accept a variable argument instead of a fixed argument list. This can be handy where the developer is not sure of the
By default, line numbers are not turned on in SQL Developer. To turn them on, go to Tools ? Preferences: Click on the + next to Code Editor. Click on
The LCASE() function simply converts the value of a field to lowercase. Syntax: SELECT LCASE(column_name) FROM table_name;
There has been a lot of discussion regarding which of the two most popular Web servers is better. In this article, we will try to compare their characteristics and performance.
There are many instances when we struggle to find out which port is being used by our applications. On Windows, you can use the same netstat command, where the filtering
The Webbrowser control does not show the notifications of the document like a) downloading web page.. b) resolving proxy… c) hyperlink url’s You can quickly enable this by using the StatusTextChanged Event of the webbrowser control. It is a two-step process: Step 1: Attach an event handler to the Webbrowser’s StatusTextChanged event, Like myWebBrowser.StatusTextChanged += new EventHandler(myWebBrowser_StatusTextChanged); Step 2: Use the Webbrowser’s StatusText property to retrieve the current status notification. Create the event handler. private void myWebBrowser_StatusTextChanged(object sender, EventArgs e) { //get the current status text from the webbrowser control //and assign it to a control in the status bar. statusStrip1.Text = webBrowser1.StatusText; }
Use the following method to generate random passwords. private string GenerateRandomPassword(int minLength, int maxLength) { StringBuilder randomPassword = new StringBuilder(); Random rand = new Random((int)DateTime.Now.Ticks); int randLength = rand.Next(minLength, maxLength);
ASP.NET Core is the latest Web application development framework from Microsoft. It is a significant redesign of the legacy ASP.NET framework and has already become widely popular. ASP.NET Core is
Failing test after expiring the set period of time in Mockito: @Timed(millis=2000)public void testTwoSecondTimeout(){ // some logic that should not take longer than 2 seconds to execute}
Method Overloading means that you can have different methods having the same code, but with different parameters. Here is an example: class MyMath{ public static int Add(int number1, int number2)
Have you dropped a table by mistake and want to restore it? In some cases you can. Let’s say you’ve run this statement: DROP TABLE yourtable; Now, you want to
In this article, I’ll introduce you to Cloud platforms, discuss the services they provide, the cost (not just monetary cost) and the problem of lock-in. I’ll also discuss hybrid systems
