Below code snippet could help you,
FileEntry fileEntry = DLAppServiceUtil.getFileEntry(repositoryId, CREATED_FOLDER_ID, fileName);
In above, you have pass repositoryId could be equivalent to groupId which you can get it from themedisplay.getGroupId(), your folderId and fileName
you can get folderId by below code,
long FOLDER_ID = 0;
long repositoryId = themeDisplay.getScopeGroupId();
long parentFolderId = DLFolderConstants.DEFAULT_PARENT_FOLDER_ID;
List<Folder> lFolder = DLAppServiceUtil.getFolders(repositoryId, parentFolderId);
for (Folder folder : lFolder)
{
if (folder.getName().equalsIgnoreCase(FOLDER_NAME))
{
FOLDER_ID = folder.getFolderId();
break;
}
}
Please let me know if it helps