java.lang.NumberFormatException: empty String
at java.lang.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:983)
at java.lang.Double.parseDouble(Double.java:220)
at test3.init(test3.java:19)
at sun.applet.AppletPanel.run(AppletPanel.java:353)
at java.lang.Thread.run(Thread.java:534)

上のエラーは何ですか？