Learn Servlet with Free Lessons & Tips

In Java Servlets, ServletConfig is a configuration object unique to a single servlet instance, whereas ServletContext is a global object shared across the entire web application. Both interfaces are part of the javax.servlet (or jakarta.servlet) package and help manage initialization parameters without hardcoding them into Java source files.

A Java Servlet is a Java class that extends the capabilities of a server, typically a web server, by allowing it to handle dynamic content and interact with web clients. Servlets are a core component of Java-based web applications and are often used to process requests from web browsers and generate dynamic responses, such as HTML pages.

If they give dynamic response like html page

First, understand that JavaScript and Java completely two different languages. Moreover JavaScript's official name is ECMAScript. So the JavaScript AKA ECMAScript was used basically for frontend web page design in web development. Only for front-end page design animation and control. Though after introduction of NodeJS the ECMAScript/JavaScript is also used for server side.

Now come to Servlet and JSP. These both are progrmmed in Java language in web development from Java's early stage of evolution. Yes there is slight difference between the two. 'Servlet' is a piece of code written in purly Java code and sit on server and handle client-side requests and send output based on the program/code that is handles by another code of Java here like JSP too. So, in JSP (Java Server Pages) programming one can mix Java (core) code and HTML, CSS, JavaScript code (that is client-side browser code output). A JSP code may or may not communicate with servlet to produce the HTML+CSS+JavaScript web page.

In one line:
JavaScript = frontend interactivity, Servlet = backend logic, JSP = backend view (UI generation).

Java Servlets are primarily used to collect user requests from a web browser, process backend business logic, and dynamically generate web content (like HTML, JSON, or XML) to send back as a response. They act as a foundational server-side layer that allows Java applications to communicate seamlessly with web clients over the HTTP protocol.

Java Servlets handle multiple requests concurrently using a single servlet instance paired with a multithreaded architecture managed by the web container (such as Tomcat or Jetty). Instead of creating a new servlet object for every user, the container spawns or assigns a new lightweight Java thread from a managed pool for every incoming HTTP request

Budget-friendly Java hosting (India)
01. Very cheap (₹200–₹500/month)
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a) HostingHome, Starts ~₹259/month, Private Tomcat + MySQL + SSL included

b) HIOX India, Starts ~₹299/month, Supports JSP, Servlets, Tomcat, MySQL

c) eWebGuru, Starts ~₹249/month, Basic Java + MySQL support


02. For college projects / small apps
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a) Ultra cheap VPS (₹100–₹500/month), DomainHostly, Plans from ~₹94/month (VPS with Tomcat support). But you need to install Tomcat + MySQL yourself.


03. Slightly higher but stable (₹500–₹1000/month)
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a) EsteemHost, Starts ~₹699/month, Dedicated Tomcat + unlimited MySQL
But it is for real serious projects / portfolio websites.


If you are beginner, go with shared Java hosting.
If you want real experience, use VPS (install Tomcat manually)
Avoid normal cheap hosting (PHP ones) they don't support JSP/Servlet

There are some free options too, like
Oracle Cloud Free Tier (VPS)
Tomcat + MySQL, Free but setup is a bit technical

Alternatives to JSP (view/templating layer):

• Thymeleaf — most common modern replacement, natural HTML templating, integrates cleanly with Spring Boot
• FreeMarker — template engine, still used in some legacy/enterprise apps
• Mustache — logic-less templates, lightweight
• React / Angular / Vue — the real modern default; backend just returns JSON (REST API), frontend handles all rendering client-side. Most new apps go this route now instead of server-side templating.

Servlet = low-level Java mechanism that handles raw HTTP requests/responses (doGet, doPost, etc.) — general purpose, can output anything (HTML, JSON, etc.), can maintain session state.

RESTful web service = an architectural style for designing resource-based APIs — uses HTTP verbs (GET/POST/PUT/DELETE) mapped to CRUD, typically returns JSON, and should be stateless.

Nutshell :
Servlet = how requests are received;
REST = how your API should be designed/structured.

Why banks use Java + servlets for netbanking:

1. Mature & stable — 25+ years battle-tested, low-risk for financial systems
2. Strong transactions — JTA/JDBC handle ACID transactions well (critical for fund transfers)
3. Security ecosystem — Spring Security, JAAS, long track record trusted by regulators
4. Compliance-friendly — built-in audit logging, session/access control aligns with PCI-DSS/RBI norms
5. Legacy integration — core banking systems (COBOL/Java/mainframes) integrate easily via Java
6. Fits the use case — netbanking is mostly request-response, not high-concurrency streaming, so blocking servlet model works fine
7. Talent pool — huge, stable Java/Spring developer base
8. Enterprise vendor support — WebLogic/WebSphere/JBoss are built around servlets

Caveat: newer fintechs/neobanks use reactive stacks (WebFlux, Node.js, Go) for high-scale real-time needs — but traditional banks stick with servlets for stability + compliance, not raw performance.

No. Servlets are the traditional foundation (Spring MVC, JAX-RS/Jersey, Struts all run inside a servlet container like Tomcat, using blocking thread-per-request).

But reactive/non-blocking frameworks skip servlets entirely, running on Netty instead: Spring WebFlux, Vert.x, Micronaut (Netty mode), Quarkus (reactive), Play. These use event-loop I/O for better concurrency at scale.

Servlet-based = traditional blocking stack. Non-servlet = reactive stack (Netty-based), used when you need high concurrency without a thread per request.