This is not true. You could link the libraries as normal while maintaining your proprietary code. The GPL only asks you to release the code if a) you mix your proprietary code without separation from the GPL code b) you distribute the software to 3rd party. b) rarely happens if you sell the device as a closed/embedded system.

Also, they could use BSD code as well that comes with a more permissive MIT licence.

This is not true. Only the LGPL allows you to link to an open source library. That is why OpenJDK has a classpath exception (http://programmers.stackexchange.com/questions/119436/what-d...).

GPL requires you to release the source code to the customer of your software upon request. The person who buys the phone is the customer.

Correct in some way. Given the source code, e.g. Drupal (GPL v2), if you develop a proprietary module that can be shipped independently but relies on the Drupal Core or other GPL module, you still not violate GPL. It doesn't matter you need to compile it or not, at the end, most scripting language is compiled to bytecode in some for of JIT.

I mentioned GPL in general, not dissecting to the various version, because the parent reply was about Google's fear of GPL (in general).

OpenJDK was not pure GPL but rather GPL+classpath exception.

Ah, I see, my bad