diff --git a/httpclient5-osgi/src/main/java/org/apache/hc/client5/http/osgi/impl/HttpProxyConfigurationActivator.java b/httpclient5-osgi/src/main/java/org/apache/hc/client5/http/osgi/impl/HttpProxyConfigurationActivator.java
index ef02c9649..091bf8eaa 100644
--- a/httpclient5-osgi/src/main/java/org/apache/hc/client5/http/osgi/impl/HttpProxyConfigurationActivator.java
+++ b/httpclient5-osgi/src/main/java/org/apache/hc/client5/http/osgi/impl/HttpProxyConfigurationActivator.java
@@ -95,14 +95,14 @@ public final class HttpProxyConfigurationActivator implements BundleActivator, M
         // ensure we receive configurations for the proxy selector
         final Hashtable<String, Object> props = new Hashtable<>();
         props.put(Constants.SERVICE_PID, getName());
-        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders(Constants.BUNDLE_VENDOR));
+        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders().get(Constants.BUNDLE_VENDOR));
         props.put(Constants.SERVICE_DESCRIPTION, PROXY_SERVICE_FACTORY_NAME);
 
         configurator = context.registerService(ManagedServiceFactory.class, this, props);
 
         props.clear();
         props.put(Constants.SERVICE_PID, TRUSTED_HOSTS_PID);
-        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders(Constants.BUNDLE_VENDOR));
+        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders().get(Constants.BUNDLE_VENDOR));
         props.put(Constants.SERVICE_DESCRIPTION, TRUSTED_HOSTS_SERVICE_NAME);
         trustedHostConfiguration = context.registerService(ManagedService.class,
                                                            new OSGiTrustedHostsConfiguration(),
@@ -110,7 +110,7 @@ public final class HttpProxyConfigurationActivator implements BundleActivator, M
 
         props.clear();
         props.put(Constants.SERVICE_PID, BUILDER_FACTORY_SERVICE_PID);
-        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders(Constants.BUNDLE_VENDOR));
+        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders().get(Constants.BUNDLE_VENDOR));
         props.put(Constants.SERVICE_DESCRIPTION, BUILDER_FACTORY_SERVICE_NAME);
         clientFactory = context.registerService(HttpClientBuilderFactory.class,
                                                 new OSGiClientBuilderFactory(context,
@@ -121,7 +121,7 @@ public final class HttpProxyConfigurationActivator implements BundleActivator, M
 
         props.clear();
         props.put(Constants.SERVICE_PID, CACHEABLE_BUILDER_FACTORY_SERVICE_PID);
-        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders(Constants.BUNDLE_VENDOR));
+        props.put(Constants.SERVICE_VENDOR, context.getBundle().getHeaders().get(Constants.BUNDLE_VENDOR));
         props.put(Constants.SERVICE_DESCRIPTION, CACHEABLE_BUILDER_FACTORY_SERVICE_NAME);
         cachingClientFactory = context.registerService(CachingHttpClientBuilderFactory.class,
                                                        new OSGiCachingClientBuilderFactory(context,