Can we change file name like "MainActivity.java" to "ab.java" in proGuard, if yes than pls send me that code because i don't know how to put rules in ProGuard Confing file.
Activity class that are referenced from your AndroidManifest.xml can not be renamed (aka obfuscated) by ProGuard.
This is due to the aapt process which will automatically create rules like this:
# view AndroidManifest.xml #generated:14
-keep class com.example.HelloWorldActivity { <init>(...); }
If you need to obfuscate also such classes, you will need to use a commercial obfuscator like DexGuard.