Hi all, Am 10.12.20 um 01:59 schrieb Peter Kovacs: > Thank you Rony for the Java deep dive.
+1 And BTW: https://www.youtube.com/watch?v=p4DeOilMOQA Regards, Matthias > > On 08.12.20 19:11, Rony G. Flatscher (Apache) wrote: >> Hmm, just some thoughts and pointers that may be helpful in the >> context of the current Java and >> possibly HSQL discussions. >> >> Ad Java and OpenOffice >> >> IMHO Java has been fulfilling Sun's original promise "write >> once, run everywhere" in a very >> impressive way for decades by now! When Sun (being the inventor >> of Java) bought Star Division >> to acquire StarOffice and making the source also available via >> openoffice.org, Sun also had the >> Java interfaces put into the office suite, such that Java >> programmers would be able to interface >> with OOo (using "OOo" to also mean AOO and the LO-fork) via UNO >> to this very day, and also >> enabling Java to become an additional programming language to >> C++ to create OOo packages. This >> has been some achievement and to me has been impressive to this >> very day! >> >> Java AOO components and Java applications interacting with AOO >> have been working for almost >> decades without a need of change! (Also such applications would >> be deployable on different >> operating systems without a need to rewrite and recompile them!) >> >> Discussing removing Java dependencies given this history and >> integration makes me a little bit >> nervous if looking at some of the arguments, which may go back >> to misconceptions, hear-say and >> possibly wrong information published about Java (like Oracle's >> change in its license would make >> it impossible for software XXX to continue to use it ... which >> simply is not the case). >> >> The scripting interface to OOo is written in Java. Therefore it >> has become possible to use the >> Java implemented scripting languages JavaScript and BeanShell to >> create OOo macros, besides OOo >> Basic and Python. In addition - as others have done also - I >> authored a little package that uses >> the OOo scripting interface in order to make another scripting >> language (ooRexx [1]) available >> as an OOo macro language (one package creates a bidirectional >> bridge between ooRexx and Java >> [2], the other package camouflages UNO as ooRexx and exploits >> the UNO reflection mechanism to >> make it easy on programmers to interface with OOo [3]), so this >> is one reason, why being a >> little bit nervous about a possible wrong assessment of Java... >> >> Ad Java Distributions >> >> It seems that many people think that Java is only available in a >> proprietary form from Oracle >> [4], which changed its license terms for its Java 1.8/8 and up, >> around the time when modular >> Java (Java 9) got released. Oracle is regarded to be the owner >> of Java and therefore people tend >> to think that there is no open-source, free alternative >> available, which is not correct. >> >> Enter "OpenJDK" [5] the open-source version of Java: this allows >> you to use Java for free (it is >> GPL with the CLASSPATH exception license such that your code >> using it does not fall under GPL >> automatically). With the modular versions of Java, starting with >> Java 9, one is even able to >> create one own's Java (runtime environment, JRE) by combining >> the Java modules one wishes to >> deploy[6]. (This would even open up the opportunity for OOo to >> create and distribute its own >> tailored JRE, should such a need arise.) >> >> If you do not feel inclined to create your own JRE (Java >> runtime-environment) then you can >> download Java=OpenJDK JRE for your particular platform from e.g. >> AdoptOpenJDK [7], Liberica [8] >> or Zulu [9] to name a few. >> >> So Java is available in an open-source and free form with the >> term OpenJDK (open Java >> development kit) [5]. >> >> One tidbit in this "license" context: programmers who wish to >> contribute to Java/OpenJDK must >> sign an "OCA" (Oracle contributer agreement [15]) giving more or >> less all rights on the >> contributed software to Oracle which then makes the software >> available to the OpenJDK with GPL >> and the CLASSPATH exception. Something that Sun had done with >> software contributed to OOo. This >> BTW allowed later Oracle (after buying Sun and acquiring all of >> Sun's software rights) to >> contribute the OOo source code to the Apache software >> foundation, making it in the end possible >> to create and release AOO under the Apache license! (BTW, one >> would be able to release one >> own's, contributed code with additional, different licenses. >> Something that would also be >> possible for e.g. LO-contributors, but many are not aware of >> this it seems.) >> >> Ad Java 1.8/8 Versus Java 9 and Later ... >> >> Java 9 got introduced in the fall of 2017 [10]. There are a few >> notable changes: >> >> * one being that Java has been finally modularized: internal >> and reflective code now is >> access-based (using the package java.lang.invoke), such that >> setAccessible as used in the >> prior versions via the java.lang.reflect package in order to >> invoke reflectively will not be >> allowed anymore. In the transition phase this may cause >> many, many problems with code that >> was created prior to Java 9, such that for some time the >> modularized versions of Java will >> tolerate access via java.lang.reflect as in the past (and >> there are even provisions in place >> to have command-line arguments to extend these permissions >> for a longer period with newer >> versions of modularized Java). (Where java.lang.reflect >> would be usable to invoke a method >> in the otherwise inaccessilbe sun-package, java.lang.invoke >> will not allow that if the >> module is not exported, rather one needs to go up the >> inheritance tree to find a class in an >> accessible/exported module and invoke the method via that >> class' method object), >> >> * one can create one own's Java runtime environment (JRE) from >> the Java modules [6]; >> Java/OpenJDK 11 for instance does not contain the four >> JavaFX modules by default (a >> separate, active project, OpenJFX [16]) anymore; >> Java/OpenJDK 15 removes Nashorn >> (JavaScript), however at the end of November a proper >> Nashorn (JavaScript) module was made >> available that can be mixed into one own's modular JRE >> (again look at the sample in [6] to >> save yourself some research time) of Java 15 or later, >> >> * the release cycle of Java/OpenJDK had been changed to six >> (!) months: hence there have been >> two major releases of Java/OpenJDK per year since then, the >> latest one being Java/OpenJDK 15 >> as of September 2020. One purpose supposedly was to make it >> possible to add new features to >> the Java/OpenJDK language quicker than in the past. The LTS >> (long-term support) versions are >> then roughly comparable to the classic release cycles of >> Java/OpenJDK, cf. [10]. >> >> If you look at the Java/OpenJDK versions [10] you will see >> "LTS", where Java 8 will be serviced >> until 2030 (!) and the modular LTS version Java/OpenJDK 11 will >> be serviced until September >> 2026, another six years from now. >> >> Ad HSQL >> >> It seems that the rather old version of AOO's HSQL may have been >> caused by sticking to older >> versions of Java. HSQL [11] states that the HSQL version 2.3.8 >> is based on Java 1.6/6, and its >> latest HSQL version 2.5.1 (as of June 2020) is based on >> Java/OpenJDK 1.8/8. No idea whether >> 2.3.8 or 2.5.1 break with the older APIs that the current AOO >> employs. (There is an interesting >> comparison of the properties of HSQL and H2 [12] at [13]. For >> completeness in the context of the >> discussions, the homepage of Apache Derby: [14].) >> >> With this information, hopefully, Java remains as a first citizen in >> AOO! >> >> Ceterum censeo, Java should remain as a first citizen in AOO! >> :) >> >> HTH, >> >> ---rony >> >> >> [1] ooRexx (implemented in C++): >> <https://sourceforge.net/projects/oorexx/files/oorexx/5.0.0beta/> >> >> [2] BSF4ooRexx (Java bridge a mixture of C++, Java and ooRexx): >> <https://sourceforge.net/projects/bsf4oorexx/files/beta/20200928/> >> >> [3] "Scripting Apache Office", slides, ApacheCon Europe 2012, Germany: >> <AutoJava-BSF4ooRexx-04-OOo-ACE12.pdf >, UNO programming, programming >> swriter, scalc, sdraw, >> simpress, URE (UNO runtime environment) >> >> [4] Oracle's Java: <https://java.com/> >> >> [5] OpenJDK: <https://openjdk.java.net/> >> >> [6] "Setup Environment for Java/OpenJDK (2020-05-29)", slides, WU >> Vienna/Austria: >> <http://wi.wu.ac.at/rgf/wu/lehre/autojava/material/foils/AutoJava-BSF4ooRexx-08-Environment.pdf >> > >> >> [7] "AdoptOpenJDK" OpenJDK/Java: <https://adoptOpenJDK.net>; this >> version even allows you to even >> pick the JVM to run Java >> >> [8] "Liberica" OpenJDK/Java: <https://bell-sw.com/>, look for "full >> Liberica", if you want the >> JavaFX modules to be available >> >> [9] "Zulu" OpenJDK/Java: <https://www.azul.com/downloads/>, look for >> "JDK FX", if you want the >> JavaFX modules to be available >> >> [10] "Java version history", Wikipedia: >> <https://en.wikipedia.org/wiki/Java_version_history >> >> [11] "HyperSQL", Homepage: <http://hsqldb.org/> >> >> [12] "H2 Database Engine", Homepage: <https://www.h2database.com/> >> >> [13] "System Properties Comparison H2 vs. HyperSQL", a current article: >> <https://db-engines.com/en/system/H2%3BHyperSQL> >> >> [14] "Apache Derby", homepage: <https://db.apache.org/derby/> >> >> [15] "Oracle's Contributor Agreement (OCA)": >> <https://www.oracle.com/technical-resources/oracle-contributor-agreement.html> >> >> >> [16] "OpenJFX", homepage: <https://openjfx.io/ >> >> >> >>
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