Adapt to Spring Framework 7 changes.

Closes gh-949

Author: mp911de

pom.xml

@@ -47,7 +47,7 @@
 		<netty.version>4.2.7.Final</netty.version>
 		<nullaway.version>0.12.10</nullaway.version>
 		<okhttp3.version>3.14.9</okhttp3.version>
-		<spring.version>7.0.0-RC3</spring.version>
+		<spring.version>7.0.0-SNAPSHOT</spring.version>
 		<spring-data-bom.version>2025.1.0-RC2</spring-data-bom.version>
 		<spring-security-bom.version>7.0.0-M3</spring-security-bom.version>
 		<reactor.version>2025.0.0-RC1</reactor.version>

spring-vault-core/src/main/java/org/springframework/vault/client/VaultClients.java

@@ -25,6 +25,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.http.converter.AbstractHttpMessageConverter;
 import org.springframework.http.converter.ByteArrayHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.StringHttpMessageConverter;
@@ -119,9 +120,12 @@ public static RestClient createRestClient(VaultEndpointProvider endpointProvider
 			.uriBuilderFactory(createUriBuilderFactory(endpointProvider))
 			.configureMessageConverters(clientBuilder -> {
 
-				clientBuilder.customMessageConverter(new ByteArrayHttpMessageConverter());
-				clientBuilder.customMessageConverter(new StringHttpMessageConverter());
-				clientBuilder.jsonMessageConverter(JacksonCompat.instance().createHttpMessageConverter());
+				AbstractHttpMessageConverter<Object> converter = JacksonCompat.instance().createHttpMessageConverter();
+
+				clientBuilder.addCustomConverter(new ByteArrayHttpMessageConverter());
+				clientBuilder.addCustomConverter(new StringHttpMessageConverter());
+				clientBuilder.addCustomConverter(converter);
+				clientBuilder.withJsonConverter(converter);
 			});
 
 		builderCustomizer.accept(builder);