[JENKINS-25601] Noting merge of #1499.

changelog.html

@@ -61,6 +61,9 @@
   <li class=bug>
     Folder loading broken when child item loading throws exception.
     (<a href="https://issues.jenkins-ci.org/browse/JENKINS-22811">issue 22811</a>)
+  <li class=bug>
+    Amend <code>JAVA_HOME</code> check to work with JDK 9.
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-25601">issue 25601</a>)
   <li class=bug>
     Better support functional tests from Gradle-based plugins.
     (<a href="https://issues.jenkins-ci.org/browse/JENKINS-26331">issue 26331</a>)

core/src/main/java/hudson/model/JDK.java

@@ -182,7 +182,11 @@ public String getDisplayName() {
         @Override protected FormValidation checkHomeDirectory(File value) {
             File toolsJar = new File(value,"lib/tools.jar");
             File mac = new File(value,"lib/dt.jar");
-            if(!toolsJar.exists() && !mac.exists())
+
+            // JENKINS-25601: JDK 9+ no longer has tools.jar. Keep the existing dt.jar/tools.jar checks to be safe.
+            File javac = new File(value, "bin/javac");
+            File javacExe = new File(value, "bin/javac.exe");
+            if(!toolsJar.exists() && !mac.exists() && !javac.exists() && !javacExe.exists())
                 return FormValidation.error(Messages.Hudson_NotJDKDir(value));
 
             return FormValidation.ok();