Update download servlet to try-with-resources block. (#4453)

javax-servlets/src/main/java/com/baeldung/servlets/DownloadServlet.java

@@ -4,7 +4,6 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
-import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
@@ -15,21 +14,19 @@ public class DownloadServlet extends HttpServlet {
     private final int ARBITARY_SIZE = 1048;
 
     @Override
-    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
         resp.setContentType("text/plain");
         resp.setHeader("Content-disposition", "attachment; filename=sample.txt");
-        
-        OutputStream out = resp.getOutputStream();
-        InputStream in = req.getServletContext().getResourceAsStream("/WEB-INF/sample.txt");
 
-        byte[] buffer = new byte[ARBITARY_SIZE];
-        
-        int numBytesRead;
-        while ((numBytesRead = in.read(buffer)) > 0) {
-            out.write(buffer, 0, numBytesRead);
+        try (InputStream in = req.getServletContext().getResourceAsStream("/WEB-INF/sample.txt"); 
+            OutputStream out = resp.getOutputStream()) {
+            
+            byte[] buffer = new byte[ARBITARY_SIZE];
+            
+            int numBytesRead;
+            while ((numBytesRead = in.read(buffer)) > 0) {
+                out.write(buffer, 0, numBytesRead);
+            }
         }
-        
-        in.close();
-        out.flush();
     }
 }