Check if there is enough memory before allocating byte array

I need to load a file into memory. Before I do that I want to make sure that there is enough memory in my VM left. If not I would like to show an error message. I want to avoid the OutOfMemory exception.

Approach:

1. Get filesize of my file
2. Use Runtime.getRuntime().freeMemory()
3. Check if it fits

Would this work or do you have any other suggestions?