This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Excel files begin with 0xE11AB1A1E011CFD0 but the file you're using is a tab separated file which POI can't read. You need to either use a different library like opencsv, or save in the excel format (xls/xlsx).
Although this is a Java forum, I'm not going to assume that you aren't open to other options. Especially because there isn't anything in your question about using only Java.
When it comes to Microsoft Office, I'd recommend using Microsoft technology. VSTO provides native support for reading Excel documents. You could use VSTO with C# to read the Excel file and Oracle native driver for .NET (ODP.NET) to update the database.
Amir Keibi wrote:Although this is a Java forum, I'm not going to assume that you aren't open to other options. Especially because there isn't anything in your question about using only Java.
A questionable non-assumption, given that this is the JavaEE forum, so we're presumably talking about a server-side issue. Assuming that I might be open (or even be able) to using Microsoft technology on a server that is otherwise used to run JEE (and thus is likely Linux) is quite a leap.