public class checkMail {
  public static void main(String[] args) {

          String host = "pop.gmail.com";// change accordingly
        String mailStoreType = "pop3";
        String username = "yourmailid@gmail.com"; // change accordingly
        String password = "****";// change accordingly

        check(host, mailStoreType, username, password);
   }

  private static void check(String host, String mailStoreType,String username, String password) {

        try {
              //create properties field
              Properties properties = new Properties();
              properties.put("mail.pop3.host", host);
              properties.put("mail.pop3.port", "995");
              properties.put("mail.pop3.starttls.enable", "true");

              // Get a Session
              Session emailSession = Session.getDefaultInstance(properties);


            //create the POP3 store object and connect with the pop server
              Store store = emailSession.getStore("pop3s");
              store.connect(host,username,password);

            //create the folder object and open it
              Folder emailFolder = store.getFolder("INBOX");
              emailFolder.open(Folder.READ_ONLY);

           // retrieve the messages from the folder in an array and print it
              Message[] messages = emailFolder.getMessages();
              System.out.println("messages.length---" + messages.length);

              for (int i = 0, n = messages.length; i < n; i++) {
                  Message message = messages[i];
                  System.out.println("---------------------------------");
                  System.out.println("Email Number " + (i + 1));
                  System.out.println("Subject: " + message.getSubject());
                  System.out.println("From: " + message.getFrom()[0]);
                  System.out.println("Text: " + message.getContent().toString());
               /*=====================  To and CC starts here ===============================*/
                  System.out.println("n main data starts here");
                  Address[] toList = message.getRecipients(RecipientType.TO);
                Address[] ccList = message.getRecipients(RecipientType.CC);
                System.out.println("t To: " + toList);
                System.out.println("t CC: " + ccList);

               }

              //close the store and folder objects
              emailFolder.close(false);
              store.close();

              } catch (MessagingException e) {
                 e.printStackTrace();
              } catch (Exception e) {
                 e.printStackTrace();
              }

  }

Errors:
javax.mail.MessagingException: Connect failed;
  nested exception is:
      java.net.ConnectException: Connection refused: connect
      at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:209)
      at javax.mail.Service.connect(Service.java:295)
      at javax.mail.Service.connect(Service.java:177)
      at servion.checkMail.check(checkMail.java:44)
      at servion.checkMail.main(checkMail.java:24)
Caused by: java.net.ConnectException: Connection refused: connect
      at java.net.PlainSocketImpl.socketConnect(Native Method)
      at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
      at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
      at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
      at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
      at java.net.Socket.connect(Socket.java:525)
      at java.net.Socket.connect(Socket.java:475)
      at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:321)
      at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:237)
      at com.sun.mail.pop3.Protocol.<init>(Protocol.java:112)
      at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:260)
      at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:205)
      at javax.mail.Service.connect(Service.java:295)
      at javax.mail.Service.connect(Service.java:176)
      at servion.checkMail.check(checkMail.java:41)
      at servion.checkMail.main(checkMail.java:23)