解决方案是更改此行
URL url = new URL("https://redmine.xxx.cz/time_entries.xml");进入这行
URL url = new URL(null, "https://redmine.xxx.cz/time_entries.xml", new sun.net.www.protocol.https.Handler());

解决方案是更改此行
URL url = new URL("https://redmine.xxx.cz/time_entries.xml");进入这行
URL url = new URL(null, "https://redmine.xxx.cz/time_entries.xml", new sun.net.www.protocol.https.Handler());