Code simplification using the methods that we have instead

[verhas]

of retyping their functionality. We expect the users of the library to use the provided methods, then we have to use these methods in the library code where it absolutely makes sense.

[coveralls]

Coverage increased (+0.04%) to 95.102% when pulling 62604b3 on verhas:functions-vp-20200203-3 into bd147ae on apache:master.

[garydgregory]

@verhas,
May you please resolve conflicts here?
Thank you!
Gary

[verhas]

I issued the

git remote add upstream git@github.com:apache/commons-lang.git
git fetch upstream
git checkout functions-vp-20200203-3
git merge upstream/master

commands. Then I resolved the conflicts in IntelliJ that were only in Functions.java and now it shows three other files changed. I do not understand why. Probably I have to learn more git. Sorry.

I do not know if it really messes something up if it gets merged or just GIT is showing some diffs it should not.

[garydgregory]

@verhas this PR looks all messed up compared to what was here before. Learning more about git is a good thing no matter what ;-)