I want to integrate a report writer in our web application. Right now , we have some fixed reports but I want customers to use data in system freely with their own custom reports. I have searched for this using google , I get tons of answers. If some of you who have used any Java API for this, can answer, that will be great.
Jasper Reports is one of the best known. Or maybe Windward Reports is more of what you had in mind.
I'd recommend i-net Crystal-Clear 10 sporting an ad-hoc reporting component that is made to be an easy-to-use thing for non-technical users. Your users won't have to know anything about reporting at all. They simply select the kind of report, the data et voila there is a report suiting the needs.
The product is embeddable into existing web applications and even supports web-skins so your users / customers won't recognise its originally our product but yours ;)
i-net Crystal-Clear is entirely Java and offers a large API for doing all kinds of stuff with reports as well (creating, modifying …).
Disclosure: Yap. I'm working for the company who built this.