Use this PDF Creatorits a cloud based API that uses java language and also allows you to read and convert pdf files to many other formats saves your time of coding and handling errors. Best of luck.
Try this Cloud API excel file to csv converter : http://www.aspose.com/java/excel-component.aspx
it can also convert excel file to any other format you want.
Try this Excel API which inserts image in your excel document using java language and you can also use other language to insert any feature in your excel file using this API.