Rename exception variables in empty catch blocks

The Spring codebase sometimes ignores exceptions in catch blocks on
purpose. This is often called out by an inline comment.
We should make this more obvious by renaming the exception argument in
the catch block to declare whether the exception is "ignored" or
"expected".

See gh-35047

Signed-off-by: Vincent Potucek <vpotucek@me.com>
[brian.clozel@broadcom.com: rework commit message]
Signed-off-by: Brian Clozel <brian.clozel@broadcom.com>

spring-websocket/src/main/java/org/springframework/web/socket/handler/BinaryWebSocketHandler.java

@@ -41,8 +41,7 @@ public class BinaryWebSocketHandler extends AbstractWebSocketHandler {
 		try {
 			session.close(CloseStatus.NOT_ACCEPTABLE.withReason("Text messages not supported"));
 		}
-		catch (IOException ex) {
-			// ignore
+		catch (IOException ignored) {
 		}
 	}
 

spring-websocket/src/main/java/org/springframework/web/socket/handler/ExceptionWebSocketHandlerDecorator.java

@@ -93,8 +93,7 @@ public class ExceptionWebSocketHandlerDecorator extends WebSocketHandlerDecorato
 			try {
 				session.close(CloseStatus.SERVER_ERROR);
 			}
-			catch (Throwable ex) {
-				// ignore
+			catch (Throwable ignored) {
 			}
 		}
 	}

spring-websocket/src/main/java/org/springframework/web/socket/handler/TextWebSocketHandler.java

@@ -41,8 +41,7 @@ public class TextWebSocketHandler extends AbstractWebSocketHandler {
 		try {
 			session.close(CloseStatus.NOT_ACCEPTABLE.withReason("Binary messages not supported"));
 		}
-		catch (IOException ex) {
-			// ignore
+		catch (IOException ignored) {
 		}
 	}
 

spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java

@@ -412,8 +412,7 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 			try {
 				session.close(CloseStatus.PROTOCOL_ERROR);
 			}
-			catch (IOException ex) {
-				// Ignore
+			catch (IOException ignored) {
 			}
 		}
 	}