Add blank line between java and javax imports

See gh-23539

spring-websocket/src/test/java/org/springframework/web/socket/JettyWebSocketTestServer.java

@@ -17,6 +17,7 @@
 package org.springframework.web.socket;
 
 import java.util.EnumSet;
+
 import javax.servlet.DispatcherType;
 import javax.servlet.Filter;
 import javax.servlet.ServletContext;

spring-websocket/src/test/java/org/springframework/web/socket/TomcatWebSocketTestServer.java

@@ -18,6 +18,7 @@ package org.springframework.web.socket;
 
 import java.io.File;
 import java.io.IOException;
+
 import javax.servlet.Filter;
 import javax.servlet.ServletContext;
 

spring-websocket/src/test/java/org/springframework/web/socket/UndertowTestServer.java

@@ -18,6 +18,7 @@ package org.springframework.web.socket;
 
 import java.io.IOException;
 import java.net.InetSocketAddress;
+
 import javax.servlet.DispatcherType;
 import javax.servlet.Filter;
 import javax.servlet.Servlet;

spring-websocket/src/test/java/org/springframework/web/socket/adapter/standard/ConvertingEncoderDecoderSupportTests.java

@@ -17,6 +17,7 @@
 package org.springframework.web.socket.adapter.standard;
 
 import java.nio.ByteBuffer;
+
 import javax.websocket.DecodeException;
 import javax.websocket.Decoder;
 import javax.websocket.EncodeException;

spring-websocket/src/test/java/org/springframework/web/socket/adapter/standard/StandardWebSocketHandlerAdapterTests.java

@@ -17,6 +17,7 @@
 package org.springframework.web.socket.adapter.standard;
 
 import java.net.URI;
+
 import javax.websocket.CloseReason;
 import javax.websocket.CloseReason.CloseCodes;
 import javax.websocket.MessageHandler;

spring-websocket/src/test/java/org/springframework/web/socket/adapter/standard/StandardWebSocketSessionTests.java

@@ -18,6 +18,7 @@ package org.springframework.web.socket.adapter.standard;
 
 import java.util.HashMap;
 import java.util.Map;
+
 import javax.websocket.Session;
 
 import org.junit.jupiter.api.Test;

spring-websocket/src/test/java/org/springframework/web/socket/client/standard/StandardWebSocketClientTests.java

@@ -21,6 +21,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+
 import javax.websocket.ClientEndpointConfig;
 import javax.websocket.Endpoint;
 import javax.websocket.WebSocketContainer;

spring-websocket/src/test/java/org/springframework/web/socket/server/support/WebSocketHttpRequestHandlerTests.java

@@ -19,6 +19,7 @@ package org.springframework.web.socket.server.support;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.Map;
+
 import javax.servlet.ServletException;
 
 import org.junit.jupiter.api.Test;
@@ -39,6 +40,7 @@ import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
 
 /**
  * Unit tests for {@link WebSocketHttpRequestHandler}.

spring-websocket/src/test/java/org/springframework/web/socket/sockjs/client/AbstractSockJsIntegrationTests.java

@@ -28,6 +28,7 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BooleanSupplier;
+
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;

spring-websocket/src/test/java/org/springframework/web/socket/sockjs/support/SockJsServiceTests.java

@@ -19,6 +19,7 @@ package org.springframework.web.socket.sockjs.support;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
+
 import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletResponse;