[BAEL-9099] Different Ways to Get Servlet Context

 - implement a simple servlet and demonstrate four different ways of retrieving the servlet context

Author: martin-blazevic

web-modules/jakarta-servlets-2/src/main/java/com/baeldung/context/ContextServlet.java

@@ -0,0 +1,52 @@
+package com.baeldung.context;
+
+import jakarta.servlet.ServletConfig;
+import jakarta.servlet.ServletContext;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import java.io.IOException;
+
+@WebServlet("/context")
+public class ContextServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
+
+        resp.setContentType("text/plain");
+
+        // 1. Direct Access From the Servlet
+        ServletContext contextFromServlet = this.getServletContext();
+        resp.getWriter()
+            .println("1) From HttpServlet: " + contextFromServlet);
+
+        resp.getWriter()
+            .println();
+
+        // 2. Accessing Through the ServletConfig
+        ServletConfig config = this.getServletConfig();
+        ServletContext contextFromConfig = config.getServletContext();
+        resp.getWriter()
+            .println("2) From ServletConfig: " + contextFromConfig);
+
+        resp.getWriter()
+            .println();
+
+        // 3. Getting the Context From the HttpServletRequest (Servlet 3.0+)
+        ServletContext contextFromRequest = req.getServletContext();
+        resp.getWriter()
+            .println("3) From HttpServletRequest: " + contextFromRequest);
+
+        resp.getWriter()
+            .println();
+
+        // 4. Retrieving Through the Session Object
+        ServletContext contextFromSession = req.getSession()
+            .getServletContext();
+        resp.getWriter()
+            .println("4) From HttpSession: " + contextFromSession);
+    }
+}