Multi Thread

http://www.atmarkit.co.jp/fjava/rensai2/webopt04/webopt04.html

http://www.atmarkit.co.jp/fjava/rensai2/jspservlet05/jspsevlet05_1.html

http://itpro.nikkeibp.co.jp/article/COLUMN/20070820/279950/

http://hc.apache.org/httpclient-3.x/performance.html

http://hc.apache.org/httpclient-3.x/threading.html

http://hc.apache.org/httpclient-3.x/apidocs/org/apache/commons/httpclient/MultiThreadedHttpConnectionManager.html