read-only file system on emulator
I tried your answer but it didn't work.
Eventually the following Stack Overflow Answer worked.

1) android-sdk-macosx/tools/emulator -avd &lt;avdname&gt; -writable-system
2) ./adb root
3) ./adb remount
4) ./adb push &lt;local&gt;/hosts /etc/hosts

Android file host can be
/etc/hosts &lt;--- This worked for me
/etc/system/hosts
/system/etc/hosts

Check
1) ./adb shell
2) cat /etc/hosts
3) ping customsite.com