Most efficient way to create a large file (> 1GB)

Question

Hi,

I would like to know what is the most efficient way to create a very large dummy File in java. The filesize should be just above 1GB. It will be used to unit test a method which only accepts files <= 1GB.

Answer 1

Can't you make a mock which returns filesize of > 1GB? File IO doesn't sound very unit-testy to me (although that depends on what your idea of a unit test is).

Answer 2

Create a sparse file. That is, open a file, seek to a position above 1GB and write some bytes.

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