Hello, I need to extract data from a Java web application. To be specific I am looking to extract real time stock data from yahoo market tracker. can anyone please suggest any method?
You can use glorious HTTP protocol to do that. Use any language you are comfortable with (Java, C#, VB.NET, python, ruby, php) and crawl the website you are trying to get information from.
I'm not sure you can extract the data from Yahoo Market Tracker. Even if you can, you might not be allowed to - I can't see any obvious terms & conditions/licensing. I think (although I could be wrong, anyone got better info?) that you'll need to pay to get access to an API providing near realtime market data.
There is a HTTP-based Yahoo Stock Quote API you could use to get prices, described here. Very simple, returns a comma-separated list of attributes for one or more stock symbols, for example:
http://finance.yahoo.com/d/quotes.csv?s=MSFT&f=snd1l1yr
It might not be realtime enough, but it might be the best you can do for free.
I need to extract data from a Java web application
From your standpoint, the fact that it is a Java Webapp or a PHP-one or static html pages doesn't change anything. It is not because Java is backing the webapp that suddenly you get a "Java-way" to extract the info.
Now in some cases there are APIs provided allowing you to interact with the data present on the website: but once again the fact that the Webapp is a Java one or not bears no importance.