If you're just going to insult us, please stay away. We don't need your help unless you're going to be constructive.
Good units tests will catch code modifications like:
from: long getLastByteOffsetBlock() { return lastByteOffsetInBlock; } to from: long getLastByteOffsetBlock() { return lastByteOffsetInBlock-1; } I did 10 of such changes and about 60% were undetected.