jenkins: Requires Java 1.8, but no longer installable

[saschakettler]

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What you were trying to do (and why)

I'm trying to install Jenkins on a fresh Homebrew installation.

What happened (include command output)

Jenkins fails to install, as Java 1.8 is required, but no longer installable (see homebrew-cask-versions/issues/7253)

$ brew install jenkins
jenkins: Java 1.8 is required to install this formula.
JavaRequirement unsatisfied!
You can install with Homebrew Cask:
  brew cask install homebrew/cask-versions/java8
You can download from:
  https://www.oracle.com/technetwork/java/javase/downloads/index.html
Error: An unsatisfied requirement failed this build.

What you expected to happen

Have Jenkins installed with a supported JVM

Step-by-step reproduction instructions (by running brew install commands)

$ brew install jenkins
jenkins: Java 1.8 is required to install this formula.
JavaRequirement unsatisfied!
You can install with Homebrew Cask:
  brew cask install homebrew/cask-versions/java8
You can download from:
  https://www.oracle.com/technetwork/java/javase/downloads/index.html
Error: An unsatisfied requirement failed this build.

$ brew cask install homebrew/cask-versions/java8
==> Caveats
Installing java8 means you have AGREED to the license at:
  https://www.oracle.com/technetwork/java/javase/terms/license/javase-license.html

==> Satisfying dependencies
==> Downloading https://download.oracle.com/otn-pub/java/jdk/8u202-b08/1961070e4c9b4e26a04e7f5a083f551e/jdk-8u202-macosx-x64.dmg
==> Downloading from https://download.oracle.com/otn-pub/java/jdk/8u202-b08/1961070e4c9b4e26a04e7f5a083f551e/jdk-8u202-macosx-x64.dmg?AuthPara

curl: (22) The requested URL returned error: 404 Not Found
Error: Download failed on Cask 'java8' with message: Download failed: https://download.oracle.com/otn-pub/java/jdk/8u202-b08/1961070e4c9b4e26a04e7f5a083f551e/jdk-8u202-macosx-x64.dmg

Workaround

Change the formula to switch to Java 11 (Java 12 is not supported) to avoid users having to deal with outdated Java 1.8 or using an unlicensed copy by accident.

The following is my proposed changes that work fine for me:

diff --git a/Formula/jenkins.rb b/Formula/jenkins.rb
index c224540791..0ee01bdee0 100644
--- a/Formula/jenkins.rb
+++ b/Formula/jenkins.rb
@@ -11,7 +11,7 @@ class Jenkins < Formula

   bottle :unneeded

-  depends_on :java => "1.8"
+  depends_on :java => "11"

   def install
     if build.head?
@@ -20,8 +20,8 @@ class Jenkins < Formula
       system "jar", "xvf", "jenkins.war"
     end
     libexec.install Dir["**/jenkins.war", "**/jenkins-cli.jar"]
-    bin.write_jar_script libexec/"jenkins.war", "jenkins", :java_version => "1.8"
-    bin.write_jar_script libexec/"jenkins-cli.jar", "jenkins-cli", :java_version => "1.8"
+    bin.write_jar_script libexec/"jenkins.war", "jenkins", :java_version => "11"
+    bin.write_jar_script libexec/"jenkins-cli.jar", "jenkins-cli", :java_version => "11"
   end

   def caveats; <<~EOS
@@ -42,7 +42,7 @@ class Jenkins < Formula
         <array>
           <string>/usr/libexec/java_home</string>
           <string>-v</string>
-          <string>1.8</string>
+          <string>11</string>
           <string>--exec</string>
           <string>java</string>
           <string>-Dmail.smtp.starttls.enable=true</string>

[SMillerDev]

Apparently there's some warnings for switching to Java 11. Is there any way to resolve those issues automatically for users? In that case you could make a pull request that changes this.

[amyspark]

I think this is a duplicate of Homebrew/brew#6035 cc @Homebrew/maintainers

[SMillerDev]

Well, it'll be solved by it. It's not really a duplicate.

[claui]

@saschakettler Due to a deficiency in how Homebrew resolves Java requirements, it currently treats depends_on :java => "11" like "11+".

So even though your proposed patch is correct, it would currently cause Homebrew to lead the user to the Java 12 cask.

I hope we’ll manage to improve that so your patch can be applied afterwards. (Jenkins isn’t going to support 1.8 forever.)

[saschakettler]

The workound (installing homebrew/cask-versions/adoptopenjdk8) is working fine for me, so if no one objects, I will close this issue later.

The upgrade issues raised here (all plugins have to support Java 11 before upgrading Jenkins to use Java 11) are valid and should be dealt with properly. I'm not that deep into Homebrew development, so I can't really tell what's best. In any way, we should wait until Jenkins-LTS supports Java 11, as by then, most of the Plugins should be compatible.