A real way they could improve app quality is to improve the quality of the documentation, specifically the javadoc / references (guides are OK mostly) but that requires work from developers (since its literally embedded in the code). There are thousands of classes / methods that have no documentation whatsoever other than that they exist in the first place. No description. No tips. No mention of what happens if you pass null, or ... you get the point.
Of course, you can look at the implementation ... but that is free to change. The documentation is the contract, and at the moment its a very poor contract.