Series of Java OpenJDK 17 related questions

I have a series of Java questions that I wish to pose, probably for a person with a bit more experience within that technology domain.

-OpenJDK now comes with modules support. Will a Java3D program, namely with a main method and in the requisite main method module, still compile and run the same, with some other library, say, a 2D graphing library, such that the library was not built or compiled with in any module, but in an earlier version of java without modules?

-Why did Java even have to have a modules system, anyway?

-If I wanted a 3D Java library, as an alternative to Java3D 1.7, one that has more support for special effects, that is used in industry, but approaches something like C++ OSG (Object Scene Graph), with many more options and powers that Java3D 1.7, what comes recommended for Java?

-Java .class files and .jar files have always been very easy to decompile. Excelsior Jet is now defunct, and older versions of that will cease to be compatible with Java going into the future. There is the Bisguard tool, which I am aware of. Will java likely ever be compilable into different binary OS files? What can be done now to protect any of .class, .jar, .war, .ear classes? May this area be likely improved into the future, and how?

-The JSTL, Java Standard Tag Library, part of the JSP, Java Server Pages system, has always been incomplete. What
state is JSTL in nowadays? Will anyone ever complete it, or likely?

-It has been suggested that Java may likely name mathematics operator overriding into the future, maybe within project Valhalla. I have plans on applying that upon so-called Arbitrary precision classes, either the default ones with Java or those available through Open Source on the public internet. Is Operator Overriding very likely to be put into openJDK in the future?

-There now is no longer any Java Applet system. Will there likely be something in the future, that will run inside web browsers, supporting something similar, or even better, into the future, for Java?

-I have always found that Java development for mobile devices is very tricky. Particularly if you want to do something
like emulate the mobile phone environment in Netbeans, on a Desktop PC, as you program. Is there a java android app
at the Google Play App store? If I am against programming in the Android language for an Android smartphone, but
want to program in Java, how does Java for smartphones, presently, work, also given openJDK v 17? If I want to combine the previous 3D Java library on Android or Windows smartphone software, how may one do that?