Google Guava over Apache Commons Lang3

[koppor]

We don't have an Architectural Decision Record why we included Apache Commons Lang. We introduced the dependency within #1572.

I don't know, why Apache Commons Lang3 was chosen. The current opinion is that Guava is more modern and that new projects should use Google Guava instead of Apache Commons Lang3.

Should we replace Apache Commons Lang3 or should we just keep it, because it is not that huge and we have other class issues (see #3014).

Refs #2966 (comment)

Update

• I replaced most places where we use Apache Commons Lang3 and there is a Google Guava equivalent
• We have some places, where there is no Google Guava equivalent, so I kept that
• Moved all architecture tests to org.jabref.architecture.
• I began to use ArchUnit for checking that. However, I have issues in using the notAnnotatedWithRule (see NPE demonstration TNG/ArchUnit#19).

[Siedlerchr]

I like the guava stuff. I don't see any big advantage in the apache commons stuff which the Guava has not.
And it seems like the Guava has also an Escape method:
https://github.com/google/guava/blob/9b94fb3965c6869b0ac47420958a4bbae0b2d54c/android/guava-tests/test/com/google/common/html/HtmlEscapersTest.java

[lenhard]

I am also in favor of replacing commons lang with guava. So, if anybody wants to go ahead with this, be my guest.

[koppor]

Fun fact:

+--- com.microsoft.azure:applicationinsights-core:1.0.+ -> 1.0.8
|    +--- eu.infomas:annotation-detector:3.0.4
|    +--- commons-io:commons-io:2.4
|    +--- org.apache.commons:commons-lang3:3.1 -> 3.4
|    +--- org.apache.httpcomponents:httpclient:4.3.5 -> 4.5.2 (*)
|    \--- com.google.guava:guava:12.0.1 -> 22.0 (*)

[koppor]

HtmlToUnicode is unfortunately not the same as Escaping HTML:

Ε gets Ε instead of E 😄

[koppor]

What I stumbled upon while searching for various commons lang replacements: Eclipse Collections.

Maybe, we can reduce our memory by using Eclipse Collections?

I continue that discussion at #3023

[koppor]

• I replaced most places where we use Apache Commons Lang3 and there is a Google Guava equivalent
• We have some places, where there is no Google Guava equivalent, so I kept that
• I began to use ArchUnit for checking that. However, I have I had issues in using the notAnnotatedWithRule (see NPE demonstration TNG/ArchUnit#19), but these are resolved now.

The ArchRule doNotUseApacheCommonsLang3 reads easy:

public static final ArchRule doNotUseApacheCommonsLang3 =
        noClasses().that().areNotAnnotatedWith(ApacheCommonsLang3Allowed.class)
        .should().accessClassesThat().resideInAPackage("org.apache.commons.lang3");

However, this rule completely ignores the annotation ApacheCommonsLang3Allowed and I have no clue how to solve that.

[LinusDietz]

I really like how ArchUnit works and we should consider using it for more purposes.

I think the PR is good to go for now, although I actually dislike that we don't actually get rid of Commons Lang and even have a annotation for that.
I would suggest to open a issue on that with a beginner label that somebody can have a look how to get rid of the last Commons Lang usages.