From what I know the only way you can avoid paying a student loan is to file for bankruptcy. However, as a student you will not be successful unless you can prove to the bankruptcy court that forcing you to repay the loans would cause 'undue hardship' on your financial future.
In fact student loans have a special status under bankruptcy law. If any part of the loan debt came from a government or non-profit source, which is pretty much all of them, you will be stuck repaying your student loans even if you declare bankruptcy. The only exception is that outlined above.
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