Android hacking: hooking system functions used by Dalvik

Let's say you need to alter behavior of some Android app you do not have source code for. For example, you want to redirect all socket connect()s made to badhost.com to myhost.com or perhaps even 127.0.0.1. How this can be achieved (without having to root the device and recompile system libs) ? On normal Linux systems one can easily use dynamic linker LD_PRELOAD environment variable to let ld chan