Java Security

My program is a Java application where I read data from different text files. I am encrypting the text files using Triple DES algorithm and distributing the encrypted files with the app. When executing the app, I am decrypting them and using in the app. I have a secret key generated while doing the encryption and I am using this secret key to decrypt the data back.

My question is how do I supply the secret key with the app? Right now I am writing the secret key to a file and distributing the file with the app. What is the preferred way of supplying the secret key?

Bhaskar