Technical Notes

GET vs POST Methods in HTTP Understanding GET and POST Methods in HTTP When it comes to web development, understanding the fundamental differences between the GET and POST methods in HTTP is essential. These methods are used to send data between the client and server, but they do so in distinct ways, each with its own advantages and limitations. Let's delve into the key differences between GET and POST methods. GET Method: Data Transmission: In the GET method, data is appended to the URL as query parameters. This makes it easily visible in the browser's address bar. Single Call System: GET requests are simple and involve a single call to the server. Data Size Limit: The amount of data that can be sent via GET is limited to around 256 characters due to URL length restrictions. Speed: Data transmission is generally faster with GET reque...

Setting Up Gzip Compression for Better Web Performance Compression is a simple, effective way to save bandwidth and speed up your site. I hesitated when recommending gzip compression for speeding up your JavaScript due to problems in older browsers. But it's the 21st century. Most of my traffic comes from modern browsers, and quite frankly, most of my users are fairly tech-savvy. I don't want to slow everyone else down because somebody is chugging along on IE 4.0 on Windows 95. Google and Yahoo use gzip compression. A modern browser is needed to enjoy modern web content and modern web speed — so gzip encoding it is. Here's how to set it up. Wait, wait, wait: Why are we doing this? Before we start, I should explain what content encoding is. When you request a file like http://www.yahoo.com/index.html , your browser talks to a web server. The conversation goes a little like this: ...

Servlet Lifecycle Overview Servlet Lifecycle Overview The life cycle of a servlet can be categorized into four parts: Loading and Instantiation: The servlet container loads the servlet during startup or when the first request is made. The loading of the servlet depends on the <load-on-startup> attribute in the web.xml file. If <load-on-startup> has a positive value, the servlet is loaded with the container; otherwise, it loads when the first request is made. After loading, the container creates instances of the servlet. Initialization: After creating the instances, the servlet container calls the init() method and passes the servlet initialization parameters to it. The init() method must be called before the servlet can service any requests. Initialization parameters persist until the servlet is destroyed. The init() method is called only once t...

Servlet Methods Overview Overview of Servlet Methods A Generic servlet contains the following five methods: init() public void init(ServletConfig config) throws ServletException The init() method is called only once by the servlet container throughout the life of a servlet. This method allows the servlet to initialize and be placed into service. The servlet cannot be put into service if: The init() method does not return within a fixed time set by the web server. It throws a ServletException. Parameters: The init() method takes a ServletConfig object containing initialization parameters and servlet configuration and throws a ServletException if an exception occurs. service() public void service(ServletRequest req, ServletResponse res) throws ServletExceptio...

Servlet Containers Explained A servlet container is a compiled, executable program responsible for loading, initializing, and executing servlets. It serves as the official Reference Implementation for Java Servlet and JavaServer Pages technologies. Developed by Sun under the Java Community Process, servlets provide a powerful, platform-independent method for server-side programming, overcoming the limitations of CGI programs. The container handles a large number of requests and can hold many active servlets, listeners, and other components. Notably, the container and its objects are multithreaded, meaning each object must be thread-safe as multiple requests may be handled simultaneously. Note: A servlet container can operate standalone, without a web server, or on a different host. Types of Servlet Containers Servlet containers can be catego...

Understanding Servlets Servlets are server-side components that provide a powerful mechanism for developing server-side programs. They offer component-based, platform-independent methods for building web-based applications, without the performance limitations of CGI programs. Unlike proprietary server extension mechanisms (such as the Netscape Server API or Apache modules), servlets are server- and platform-independent. Benefits of Using Servlets This flexibility allows developers to select a "best of breed" strategy for their servers, platforms, and tools. By using servlets, web developers can create fast and efficient server-side applications that can run on any servlet-enabled web server. Since servlets run entirely inside the Java Virtual Machine (JVM), they are not dependent on browser compatibility. Servlets can access the entire family of Java APIs, includi...