Markdown: Fix compile errors on JDK 7
Markdown: Fix compile errors on JDK 7

yona-projects/yona,ahb0327/yobi,doortts/fork-yobi,bloodybear/yona,ahb0327/yobi,ihoneymon/yobi,doortts/fork-yobi,bloodybear/yona,naver/yobi,ihoneymon/yobi,yona-projects/yona,bloodybear/yona,doortts/fork-yobi,brainagenet/yobi,naver/yobi,ahb0327/yobi,naver/yobi,brainagenet/yobi,ihoneymon/yobi,brainagenet/yobi,yona-projects/yona,doortts/fork-yobi,bloodybear/yona,yona-projects/yona