thank you for answers.
I try to be more clear.
I've seen there is the archive to download any JRE and JDK I want but my question is:
If I'd like to learn the language and try to create programs runnable on any machine which version of Java is better to learn and use?
I like the modular system of Java 9/10 but If I'll write something use this feature and I run it on an another machine different from whichone I've written it, the applet try to download the correct version from website or just doesn't work?
If with a normal PC I go to java.com website and try to download Java, the browser give me the 8 version not 9 or 10... to download the 9 or 10 I've to go where you have said to me... but the "normal" user just click on "Download" not ask about the version...
So, I'm afraid to learn and program into java 10 and the user cannot use my software... what do you think?
As far as Java development, I've used NetBeans IDE since 1999, but recently NetBeans has been turned over to Apache and is not officially being supported by Oracle any longer, so you see a major stall in the development of new version of NetBeans while the community ramps up--NetBeans last release is back in Java version 8.x
Java 9 and 10: one of the nice things about java is that many of the versions are backwardly compatible, you'll have to check 8, 9, and 10 which you choose to use.
As previously pointed out the new version is 10. Much development is still being done in 8, there is always a major lag in accepting new versions due to legacy apps. Since NetBeans is stalled in Java version 8 at this point, I have not moved on and neither has many of the developers that I know--8 is a solid install.
So choosing 8, 9, or 10 for development at this point is up to you. I am still in 8 and do not find it a problem. 9 and 10 are out there and I have not seen feedback saying that developing for those versions creates a problem, but be aware that newer version may experience some rejection due to not yet having the install base.
BTW: I like NetBeans, so I and many others will not move on until NetBeans supports newer versions of Java or we get an official "Orphan Report" on NetBeans.
Thank you so much, you were very clear!