Ok I got the answer myself: After refering to this link http://docs.oracle.com/javase/7/docs/api/java/security/AccessController.html , I figured out ,that reading,writing or even deleting can be done by wraping them up in AccessController.doPrivileged method.
AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Object run() {
try {
deleteAppCacheDirectory();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
});