You can force push to existed branch + previous PR was mergeable.

You are merging faster than i'm reviewing.

@KostyaSha Sorry, I thought you reviewed original PR already.

But new commits periodically appears new :)

Note, for any null/empty/string length try search for helpers in guava/commons/collections.
With java 1.8 Objects.isNull() Obects.nonNull() will be available that will end to nicer code

if (isNull(someObject)) {

or

  public void someMethod(String arg) {
      Objects.requireNonNull("Fail", arg);

But null check from 1.8 doesn't catched by findbugs yet.