How to protect read-only data in Swing app from tampering?

First off I am new to cryptography and trying to find the best approach for a problem.
We have a Swing application that uses xml-based template files to display complex forms and validate data entry. Based on the size and complexity of the forms it was deemed better to have a distributed stand-alone application instead of a web-based solution. However, we want to ensure users do not tamper with the template rules in order to pass the validation checks. All of the xml-based template files are distributed within a single jar file.
The first thought was to build a list of check-sums of the template files and to compare the template to the approariate check-sum from within the list before loading a template. This would prevent the more casual user from tampering with the file but not someone knowledgeable in check-sum who could recalculate the CRC and update the list after making changes.
Another thought was to use a private key to encrypt the CRC list before distribution and a public key to decrypt it during execution with the keys maintained in a keystore. However, once again, an adventurous user could weed through the obfuscated code to determine the password to the keystore, create a new keystore with the same password and use its private key to regenerate the CRC list from altered templates.
I feel like there must be a simpler approach that will provide a bullet prove implementation. Any suggestions?

I think you have to re-think your design.
Whether you use Java, C#,C or C++ a hacker can look through the binary (class file, exe file etc) and after working out what is happening he can modify your code.
It is my opinion that your best bet is to use client/server but even with that you cannot keep any private data or code on the client.
You will still have to think about 'man-in-the-middle' and 'spoof site' attacks.

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