Java 17 features (#15493)

- add missing @override
- Java style array syntax
- remove redundant modifiers
- always move String constants to left side in comparisons
- simplify lambda expressions and return statements
- use replace instead of replaceAll w/o regex

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.io.openhabcloud/src/main/java/org/openhab/io/openhabcloud/internal/CloudClient.java

@@ -540,7 +540,7 @@ public class CloudClient {
             try {
                 headerValue = requestHeadersJson.getString(headerName);
                 logger.debug("Jetty set header {} = {}", headerName, headerValue);
-                if (!headerName.equalsIgnoreCase("Content-Length")) {
+                if (!"Content-Length".equalsIgnoreCase(headerName)) {
                     request.header(headerName, headerValue);
                 }
             } catch (JSONException e) {

bundles/org.openhab.io.openhabcloud/src/main/java/org/openhab/io/openhabcloud/internal/CloudService.java

@@ -380,6 +380,6 @@ public class CloudService implements ActionService, CloudClientListener, EventSu
     }
 
     private boolean supportsUpdates() {
-        return cloudBaseUrl.indexOf(CFG_BASE_URL) >= 0;
+        return cloudBaseUrl.contains(CFG_BASE_URL);
     }
 }