Gmail POP3 not getting all messages in Java application

I have enabled POP3 settings for my gmail. I am able to connect to the POP3 store using my password in a Java app. I have around 10k messages in my inbox.

When I call getMessages on the Inbox folder it returns only 280 old messages. When I call getMessages in a loop, every call returns me same messages. I also tried getMessages(start, end) but it does not return other messages than those 280.

How do I retrieve the other messages?