Use newer API for creating tmp files in RESTEasy Reactive

Author: geoand

independent-projects/resteasy-reactive/common/runtime/src/main/java/org/jboss/resteasy/reactive/common/providers/serialisers/FileBodyHandler.java

@@ -10,6 +10,7 @@
 import java.io.OutputStream;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
+import java.nio.file.Files;
 
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
@@ -32,7 +33,7 @@ public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotati
     public File readFrom(Class<File> type, Type genericType,
             Annotation[] annotations, MediaType mediaType,
             MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException {
-        File downloadedFile = File.createTempFile(PREFIX, SUFFIX);
+        File downloadedFile = Files.createTempFile(PREFIX, SUFFIX).toFile();
         if (HeaderUtil.isContentLengthZero(httpHeaders)) {
             return downloadedFile;
         }