java tomcat: what library should i use to convert images to jpg and create thumbnails on-the-fly?

I have a form that accepts image file, i want to be able to convert this image from any common format to jpg and to c开发者_JAVA技巧reate a thumbnail. what's the recommended method to achieve such a thing?

Working with latest apache-tomcat on a gentoo linux server.

thanks

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Imagemagick is a pretty solid library that a lot of people use for such a purpose.