the single instance feature won't work if the jnlp file is longer than 1024 characters

this is because in src/share/native/system.c, function sysWriteSocket, we limit the character buffer to send to 1024, which is wrong. We use this function to send over the jnlp file to the SingleInstanceServer. It is very likely that the jnlp file will contains more than 1024 characters.

one example is the webpad.jnlp included in the samples, it's very long since it contains the licence as the comment in the jnlp file.