title: Android system / system context / replace classes
body: <p>Hi I'm engineer but more from a chip/assembler x86 level. I'm new to Android. Still figuring some general things out. I have written some apps, but have a general question. If I were to write an improved version of - let's say - TextView. Is it possible to make all app's on the system using this class, basically replace TextView? How are the java classes on the Android system, are they compiled, can I replace the library? Is this protected? Thanks for help</p>