异常:No buffer space available (maximum connections reached?): connect

我的一个SWT应用程序，需要每5分钟获取一下新闻，在测试程序时报异常如下，不知是什么原因导致？
异常： No buffer space available (maximum connections reached?): connect public String getNewsContent(){
         DataInputStream dis=null;
         HttpURLConnection con = null;                
         String content="";
         StringBuffer buffer=new StringBuffer();
         try{
               String url="http://www.etnetchina.com/EtnetChinaShow/newsList.do;jsessionid=999E61E5BC3DCAE9D840465A7858B792.tomcat2?model=focusNews";
                        con = (HttpURLConnection)new URL(url).openConnection();
             con.setConnectTimeout(30000); //连接超时
             con.setReadTimeout(30000); //读操作超时'
             System.setProperty("sun.net.client.defaultConnectTimeout","60000");   
             System.setProperty("sun.net.client.defaultReadTimeout","60000");
             con.connect();
                        dis=new DataInputStream(con.getInputStream());
                        String line="";                       
                        while((line=dis.readLine())!=null){
                         try{
                                line=new String(line.trim().getBytes("iso8859-1"),"UTF-8");
                                buffer.append(line+"\n");
                         }catch(Exception e){
                         log.info("while "+e.getMessage());
                         //throw new RuntimeException();   //抛出运行时异常,上一层进行捕获!
                         break;
                         }
                        }
                        dis.close();
                        con.disconnect();
                        String newsXml=buffer.toString();
             log.info("Filtration/Interception...");
                        int n=newsXml.indexOf("<div class=\"allnewslisttext\"> ");
                        int l=newsXml.indexOf("</div> ");
                        String xml="<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
                        xml=newsXml.substring(n,l);
                        xml+="</div>";
                        RssFunction fun=new RssFunction();
                        fun.writeTextFile(xml);
                        
                        String date=this.getTime();                        DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
                        DocumentBuilder builder=factory.newDocumentBuilder();
                        Document doc=builder.parse("D:/SLDDataCenter/center/media/xgtemp.xml");                        NodeList list=doc.getElementsByTagName("li");
                        for(int i=0;i<list.getLength();i++){
                                Element node=(Element)list.item(i);
                                String dateTime=node.getElementsByTagName("span").item(0).getFirstChild().getTextContent().trim();
                                String dateTime_[]=dateTime.split("  ");
                                if(dateTime_[0].equals(date)){
                                        content+="<img src=\"\" width=\"24\"/>"+dateTime+"<img src=\"\" width=\"8\"/>"+node.getElementsByTagName("a").item(0).getFirstChild().getTextContent().trim();
                                }
                                else{
                                        content+="<img src=\"\" width=\"24\"/>"+dateTime+"<img src=\"\" width=\"8\"/>"+node.getElementsByTagName("a").item(0).getFirstChild().getTextContent().trim();
                                }
                        }
//                        log.info("轉換為繁體字!");
                        ComplexFont font=new ComplexFont();
                        String complex=font.simpleToComplex(content);                        
                        content=null;
                        content=complex;                   
                        fun.deleteFile("D:/SLDDataCenter/center/media/xgtemp.xml");
                        log.info("news success!");
                }catch(ConnectException e){
         log.info("NewsRss网站连接不通!");
         }catch(NoRouteToHostException e1){
         log.info("NewsRss掉线或网络不通异常!");
         }catch(UnknownHostException ex){
         log.info("NewsRss地址无法解析异常!"+ex.getMessage());
         }catch(Exception e){
                    log.info("Error: NewsRss!"+e.getMessage());
                }
                finally{
                        try{
                         dis.close();
                         con.disconnect();
                        }
                        catch(Exception e){}
                }
                return content;
        }