Header request

Author: sverdlov93

build-info-extractor/src/main/java/org/jfrog/build/extractor/clientConfiguration/client/artifactory/ArtifactoryManager.java

@@ -95,15 +95,18 @@ public DownloadResponse download(String downloadFrom, Map<String, String> header
 
     /**
      * Download headers and return specific header if exists
+     *
      * @param downloadFrom - path to specific artifact in Artifactory.
-     * @param headerName - specific header name to return if exists.
+     * @param headerName   - specific header name to return if exists.
      * @return - header's string value to return.
      */
     public String downloadHeader(String downloadFrom, String headerName) throws IOException {
         Header[] headers = downloadHeaders(downloadFrom);
-        for (Header header : headers) {
-            if (header.getName().equals(headerName)) {
-                return header.getValue();
+        if (headers != null) {
+            for (Header header : headers) {
+                if (header.getName().equals(headerName)) {
+                    return header.getValue();
+                }
             }
         }
         return StringUtils.EMPTY;