minor code improvements

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

de.srsoftware.oidc.api/build.gradle

@@ -13,6 +13,7 @@ dependencies {
     testImplementation 'org.junit.jupiter:junit-jupiter'
     implementation 'org.json:json:20240303'
     implementation 'org.bitbucket.b_c:jose4j:0.9.6'
+    implementation project(':de.srsoftware.utils')
 }
 
 test {

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/Client.java

@@ -1,7 +1,9 @@
 /* © SRSoftware 2024 */
 package de.srsoftware.oidc.api;
 
+
 import static de.srsoftware.oidc.api.Constants.*;
+import static de.srsoftware.utils.Optionals.nullable;
 
 import java.util.*;
 
@@ -38,7 +40,7 @@ public final class Client {
 	}
 
 	public Optional nonce() {
-		return Optional.ofNullable(nonce);
+		return nullable(nonce);
 	}
 
 	public String secret() {

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/PathHandler.java

@@ -2,6 +2,7 @@
 package de.srsoftware.oidc.api;
 
 import static de.srsoftware.oidc.api.Constants.AUTHORIZATION;
+import static de.srsoftware.utils.Optionals.nullable;
 import static java.lang.System.Logger.Level.*;
 import static java.net.HttpURLConnection.*;
 import static java.nio.charset.StandardCharsets.UTF_8;
@@ -98,7 +99,7 @@ public abstract class PathHandler implements HttpHandler {
 		}
 
 		public static Optional<String> getHeader(HttpExchange ex, String key) {
-			return Optional.ofNullable(ex.getRequestHeaders().get(key)).map(List::stream).flatMap(Stream::findFirst);
+			return nullable(ex.getRequestHeaders().get(key)).map(List::stream).flatMap(Stream::findFirst);
 		}
 
 		public static String hostname(HttpExchange ex) {