test: add empty component

vul/vul-webapp/src/main/java/EmptyFilter.java

@@ -0,0 +1,19 @@
+import javax.servlet.*;
+import java.io.IOException;
+
+public class EmptyFilter implements Filter {
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+
+    }
+
+    @Override
+    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
+        filterChain.doFilter(servletRequest, servletResponse);
+    }
+
+    @Override
+    public void destroy() {
+
+    }
+}

vul/vul-webapp/src/main/java/EmptyListener.java

@@ -0,0 +1,15 @@
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletRequestEvent;
+import javax.servlet.ServletRequestListener;
+
+public class EmptyListener implements ServletRequestListener {
+    @Override
+    public void requestDestroyed(ServletRequestEvent servletRequestEvent) {
+        ServletRequest servletRequest = servletRequestEvent.getServletRequest();
+    }
+
+    @Override
+    public void requestInitialized(ServletRequestEvent servletRequestEvent) {
+        ServletRequest servletRequest = servletRequestEvent.getServletRequest();
+    }
+}

vul/vul-webapp/src/main/java/EmptyWebSocketEndpoint.java

@@ -0,0 +1,24 @@
+import javax.websocket.Endpoint;
+import javax.websocket.EndpointConfig;
+import javax.websocket.MessageHandler;
+import javax.websocket.Session;
+import java.io.IOException;
+
+public class EmptyWebSocketEndpoint extends Endpoint implements MessageHandler.Whole<String> {
+    private Session session;
+
+    @Override
+    public void onOpen(Session session, EndpointConfig endpointConfig) {
+        this.session = session;
+        session.addMessageHandler(this);
+    }
+
+    @Override
+    public void onMessage(String message) {
+        try {
+            session.getBasicRemote().sendText("Echo: " + message);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

vul/vul-webapp/src/main/java/WebSocketConfig.java

@@ -0,0 +1,24 @@
+import javax.websocket.Endpoint;
+import javax.websocket.server.ServerApplicationConfig;
+import javax.websocket.server.ServerEndpointConfig;
+import java.util.HashSet;
+import java.util.Set;
+
+public class WebSocketConfig implements ServerApplicationConfig {
+    @Override
+    public Set<ServerEndpointConfig> getEndpointConfigs(Set<Class<? extends Endpoint>> scannedEndpointClasses) {
+        Set<ServerEndpointConfig> result = new HashSet<ServerEndpointConfig>();
+        ServerEndpointConfig config = ServerEndpointConfig.Builder
+                .create(EmptyWebSocketEndpoint.class, "/empty-ws")
+                .build();
+
+        result.add(config);
+        System.out.println("websocket init success");
+        return result;
+    }
+
+    @Override
+    public Set<Class<?>> getAnnotatedEndpointClasses(Set<Class<?>> scanned) {
+        return scanned;
+    }
+}