[FIXED] Where is JRE 11?

Issue

UPDATE:

^{(to be more clear)}

You can find JRE 8, href="https://www.oracle.com/technetwork/java/javase/downloads/java-archive-javase9-3934878.html" rel="noreferrer">JRE 9 and JRE 10 on Oracle's official website (click on each). But where is JRE 11?!

Also, JDK 11 doesn't include a JRE. I was expecting JRE to be installed with JDK.

Do final users of our apps need to install JDK?

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ORIGINAL version of the question:

I downloaded and installed Oracle JDK 11 from its official site. I installed both ..._linux-x64_bin.rpm and ..._windows-x64_bin.exe (first on a Linux machine and second on a Windows machine). But I saw an unexpected thing! Where is JRE?

This is a snapshot of installation path on CentOS 7. As you can see there is no jre folder:

# ls /usr/java/jdk-11.0.1/
bin  conf  include  jmods  legal  lib  README.html  release

Same snapshot about Oracle JDK 8 (See jre folder specially):

# ls /usr/java/jdk1.8.0_191-amd64/
bin             lib          src.zip
COPYRIGHT       LICENSE      THIRDPARTYLICENSEREADME-JAVAFX.txt
include         man          THIRDPARTYLICENSEREADME.txt
javafx-src.zip  README.html
jre             release

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Same snapshots on Windows machine:

> dir /b "C:\Program Files\Java\jdk-11.0.1" 
bin                                           
conf                                          
COPYRIGHT                                     
include                                       
jmods                                         
legal                                         
lib                                           
README.html                                   
release                                                                                     
           
> dir /b "C:\Program Files\Java\jdk1.8.0_181"  
bin                                           
COPYRIGHT                                     
include                                       
javafx-src.zip                                
jre                                           
lib                                           
LICENSE                                       
README.html                                   
release                                       
src.zip                                       
THIRDPARTYLICENSEREADME-JAVAFX.txt            
THIRDPARTYLICENSEREADME.txt 

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On Windows machine, there are also two another differences between JDK 8 and JDK 11.

1. A standalone JRE alongside JDK as you can see:

   > dir /b "C:\Program Files\Java"            
   jdk-11.0.1   
   jdk1.8.0_181 
   jre1.8.0_181 
   

2. In path C:\Program Files (x86)\Common Files\Oracle\Java:

   > dir "C:\Program Files (x86)\Common Files\Oracle\Java"                                                                   
   ...                                                                                                                   
   ...                14 java.settings.cfg                                                                  
   ...    <JUNCTION>     javapath [C:\Program Files (x86)\Common Files\Oracle\Java\javapath_target_3015921] 
   ...    <DIR>          javapath_target_3015921 
   ...
   

   As you see javapath (that is in PATH environment variable) points to javapath_target_3015921. This folder contains 3 executables of JDK 8 (that aren't links!):

   > dir /b "C:\Program Files (x86)\Common Files\Oracle\Java\javapath" 
   java.exe                         
   javaw.exe                        
   javaws.exe 
   

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Finally, I searched the web to find a standalone JRE and found out it doesn't exist!

Do final users of our programs need to install JDK?

Solution

The whole structure with Java 11 has changed. Java is now a modular platform, where you can create your own "JRE" distribution with specifically the modules that you need to run your application.

The release notes at https://www.oracle.com/technetwork/java/javase/11-relnote-issues-5012449.html have the following sentence:

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.

Documentation about jlink: https://docs.oracle.com/en/java/javase/11/tools/jlink.html

And another article about it: https://medium.com/codefx-weekly/is-jlink-the-future-1d8cb45f6306

Answered By - dunni
Answer Checked By - Clifford M. (JavaFixing Volunteer)