Develop Reference

Why is JRE 10 outdated and JRE 8 up-to-date?

I (as a non-Java kind of guy) am puzzled that my local JRE 10 installation required an update, but when updating, I get the JRE 8! This is even reported on https://java.com/en/download/more_info10.jsp:
Users who installed JRE 9 and/or JRE 10 (non Long-Term Support Releases) should remove those out-of-date versions of Java.
I would understand if JRE 11 would be the current version, but no, it's JRE 8:
If you still require Java on your computer download the latest release of JRE 8 available at java.com, which is the only currently supported major release of Java targeting desktop deployment.
How can this be?

The explanation is right there on that page you linked and quoted.
Relevant section highlighted.
"desktop deployment".
If you still require Java on your computer download the latest release
of JRE 8 available at java.com, which is the only currently supported
major release of Java targeting desktop deployment.
Short answer:
Java 9 and 10 are not a Long Term Support (LTS) release, and have expired.
Java 8 commercial supports end January 2019, public updates for personal use through December 2020 though.
Java 11 is the current and is also a LTS support release.
So todays choice is between java 8 and 11. But 11 removed applets and browser integration and other desktop technologies (JavaFX, java webstart etc). See list below and link to source. See also the Oracle white paper of 2018-03, Java Client Roadmap Update.
Further details:
Oracle has decided to stop releasing several variants of JRE on their own. As well as requiring a license for production use for newer releases. For example 32bit variants are no more, traditional desktop variants not available as there is no no java webstart and javafx is separated out since jdk 11+ etc, Oracle is more focusing on 64bit and server.
Put together with the fact that 9 and 10 are not Long term support releases (and they have expired) this leaves you with the choice of Java 8 for this particular use case for now.
JDK public updates for java 8 from oracle will end in January 2019 (and December 2020 for personal use) so at least until then is the current desktop java version of choice, from Oracle that is.
The current version of java 11, is only available as a 64bit JDK (development kit download) from oracle. No suitable desktop JRE (just the runtime).
Removed in JDK 11 release from Oracle:
Important Changes and Information
The following are some important changes in and information about this release. In some cases, additional details about the changes described below are provided in these Release Notes.
The deployment stack, required for Applets and Web Start Applications, was deprecated in JDK 9 and has been removed in JDK 11.
Without a deployment stack, the entire section of supported browsers has been removed from the list of supported configurations of
JDK 11.
Auto-update, which was available for JRE installations on Windows and macOS, is no longer available.
In Windows and macOS, installing the JDK in previous releases optionally installed a JRE. In JDK 11, this is no longer an option.
In this release, the JRE or Server JRE is no longer offered. Only the JDK is offered. Users can use jlink to create smaller custom
runtimes.
JavaFX is no longer included in the JDK. It is now available as a separate download from openjfx.io.
Source: https://www.oracle.com/technetwork/java/javase/11-relnote-issues-5012449.html

Simple: Oracle's own support roadmap lists Java 8 as having "premier" support until 2022.
Conversely, Java 9 and 10 have had their premier support lapse in March and September of 2018. Oracle's new update model ensures that non-LTS releases from Java 9 onwards are only officially supported until the new version of Java arrives.
"Current" is a bit of a strong word when it comes to Java; technically, the latest version of Java that should be used by end consumers is Java 11 (as of time of writing), since that is the current LTS. However, not all applications which use Java may be up-to-date, so it's safest to fall back to Java 8 until your application vendor informs you that it's safe to upgrade.

Perhaps that's because Java 11 deprecated modules which are present in Java 10 e.g. JAXB or Java FX. Latest Java 8 still has these modules so the software that worked on Java 10 can potentially work with Java 8.

Changes required to migrate from Oracle JDK to OpenJDK

We are planning to migrate our project from Oracle JDK to OpenJDK. I have some questions regarding the same.
After doing some analysis I found that OpenJDK will have a feature release every 6 months which is only supported until the next feature release.It's essentially a continuous stream of releases targeted to developers. Now my question is will it be a good idea to migrate to OpenJDK. Because if the
above statement is correct then we need to upgrade OpenJDK in our application every 6 months
Ref : Differences between Oracle JDK and OpenJDK
What are the basic changes required to do this migration. When I say basic changes, I mean I need to understand in very high level.One thing I know that is
Oracle JDK and Open JDK are having different jar licences. So do I need to replace all Oracle JDK jars with OpenJDK jars as its mentioned in
Migrating to OpenJDK from Oracle JDK ?
Currently we are using :
JDK 1.8
Tomcat 8
Windows Operating System for development. Services gets deployed in linux OS
Maven Build tool
Appreciate your help.
Thanks

Now my question is will it be a good idea to migrate to OpenJDK
For Java 11 you might want to, though by Java 11 they will be almost identical.
So do I need to replace all Oracle JDK jars with OpenJDK jars
I would install a version of OpenJDK and use the JARs which came with it. I wouldn't mix and match them.
JDK 1.8
I am not sure gain anything by migrating Java 8. Oracle Java 8 is still supported at least until Jan 2019. After that, you might not get any update, but you might not with OpenJDK either.
If your concern is getting support for Java 8, I suggest contacting a company which will give commercial support Java 8 such as Azul for what seemed like a reasonable price. https://www.azul.com/downloads/zulu/zulu-windows/

how to only download the 1.7 JDK, not SDK, for windows

Installing java for casual java developers has always been something of a minefield. E.g. do we need SE or EE edition for say STS/Grails, do we need the SDK or JDK? I am pretty sure I need the JDK 1.7 for EE edition. The question is, how do I get the JDK without the bloated SDK? My understanding of the SDK it that its additional tools such as glassfish, something I have no need for. Space on my SSD is a premium.
The oracle EE download page:
http://www.oracle.com/technetwork/java/javaee/downloads/index.html
only seems to allow you to download the JDK AND SDK, is there any way to install just the JDK?
I already have the 64 bit JDK installed, but sadly, STS only works with 32 bit (on windows). Will these conflict when I install both?

You can download JDK 7 here
The Java SDK and JDK are different you can check here difference between them
You can download any version of JDK from this oracle archive link, To download older version of JDK please register in the on click on download link

GlassFish Server Open Source Edition 4 is the reference implementation of the Java EE 7 specification. So you can never download Java EE itself like you do with Java SE by downloading the JDK, but you always download an application server implementing it.
Source

Issues running Java applets

Recently I'm studying Java. I had no real troubles while building normal java files to .class and execute them, but, when I started a bit with applets I haven't been able to run anything.
Before I had started Java, as developer I had already a lot of development tools (Eclipse, Visual Studio, CodeBlocks and others). So, basically, I already had JDK but downloaded it again to get updated to 1.8.
Now, I have also JRE 8 and there are no troubles in using javac.exe and java.exe to build and execute, but, after building the .class file of applet, when I load the html page, I got an error which strongly recommends me to upgrade JRE.
Just to translate it:
Current version of Java is obsolete.
Upgrade (recommended choice)
Block
Later
If I do the update, it gets me to this page http://java.com/it/download/index.jsp), but, it's the download link of JRE 1.7. As much as I know, JDK 1.8 is not beta (it's accessible a 1.9 preview) so why shall I use 1.7? Indeed, after downloading and installing, when I try to run the applet, the message above is shown again.
Is actually possible to install JRE 1.8 on Google Chrome?

I resolved it. It wasn't easy since it wasn't a real trouble of java.
I had effectively Java 7 version 55 and Java 8 (but also 7-45 and 6). Java 8 was 64-bit while Java 7 was 32.
Google Chrome (32-bit browser) used so the last version it could use. According to Oracle, it's recommended to remove older versions of java (because of security) so I removed everything but the 8, and then switched to 64-bit browser (Chromium). I left older JDK installed for compatibility development reasons.

Are Open JDK and JDK7 the same thing?

Are Open JDK and JDK7 the same thing?

Open JDK is a free (but not certified) implementation of the JLS (java language specification) where JDK7 is the next version of Sun's JDK which is currently 1.6 (or just Java 6 as the marketing devision of Sun called it).

OpenJDK was initially based only on the JDK 7.0 version of the Java platform.
Since February 15, 2008, there are two separate OpenJDK projects:
The main OpenJDK project, which is based on the JDK 7.0 version of the Java platform
The JDK 6 project, which provides an Open-source version of Java 6.0.
I hope this clears the confusion a bit.

It appears to be a Solaris<-->OpenSolaris situation, viz. there's an open-source project with as much code as possible; the fixes get transferred back to the main software, which the vendor supports and sells. OpenJDK is a project. OpenJDK version 7 and JDK7 appear to be largely but not exactly the same (per here).