How can I get the list of all files present in a directory on client machine
through signed applet?

I tried using File object ...such as this...
**********************************
File clientfolder= new File("C:\test");

String[] fileList = null;

if(clientfolder.isDirectory())
fileList = clientfolder.list();
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but it gives exception :

com.ms.security.SecurityExceptionEx[Host]: cannot access file C: est