web.xml파일을 수정합니다....
java.net.UnknownHostException: java.sun.com
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:153)
        at java.net.Socket.connect(Socket.java:452)
        at java.net.Socket.connect(Socket.java:402)
        at sun.net.NetworkClient.doConnect(NetworkClient.java:139)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:402)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:618)
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:306)
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:267)
        at sun.net.www.http.HttpClient.New(HttpClient.java:339)
        at sun.net.www.http.HttpClient.New(HttpClient.java:320)
        at sun.net.www.http.HttpClient.New(HttpClient.java:315)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:521)
        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:498)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:626)
        at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
        at org.apache.xerces.impl.XMLEntityManager.startEntity(Unknown Source)
        at org.apache.xerces.impl.XMLEntityManager.startDTDEntity(Unknown Source)
        at org.apache.xerces.impl.XMLDTDScannerImpl.setInputSource(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentScannerImpl$DTDDispatcher.dispatch(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
        at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
        at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
        at Installer.updateWebXML(Unknown Source)