Drop support for Java 8 (jenkinsci#6083)

Jenkinsfile

@@ -20,7 +20,7 @@ properties([
 
 // TODO: Restore 'Windows' once https://groups.google.com/forum/#!topic/jenkinsci-dev/v9d-XosOp2s is resolved
 def buildTypes = ['Linux']
-def jdks = [8, 11]
+def jdks = [11]
 
 def builds = [:]
 for(i = 0; i < buildTypes.size(); i++) {
@@ -29,7 +29,7 @@ for(j = 0; j < jdks.size(); j++) {
     def jdk = jdks[j]
     builds["${buildType}-jdk${jdk}"] = {
         // see https://github.com/jenkins-infra/documentation/blob/master/ci.adoc#node-labels for information on what node types are available
-        node(buildType == 'Linux' ? (jdk == 8 ? 'maven' : 'maven-11') : buildType.toLowerCase()) {
+        node(buildType == 'Linux' ? 'maven-11' : buildType.toLowerCase()) {
                 // First stage is actually checking out the source. Since we're using Multibranch
                 // currently, we can use "checkout scm".
                 stage('Checkout') {
@@ -120,7 +120,7 @@ builds.ath = {
         dir("sources") {
             checkout scm
             def mvnCmd = 'mvn --batch-mode --show-version -ntp -Pquick-build -am -pl war package -Dmaven.repo.local=$WORKSPACE_TMP/m2repo'
-            infra.runWithMaven(mvnCmd, "8", javaOpts, true)
+            infra.runWithMaven(mvnCmd, "11", javaOpts, true)
             dir("war/target") {
                 fileUri = "file://" + pwd() + "/jenkins.war"
             }

core/src/main/java/jenkins/install/SetupWizard.java

@@ -754,6 +754,7 @@ public void init(FilterConfig cfg) throws ServletException {
         }
 
         @Override
+        @SuppressFBWarnings(value = "UNVALIDATED_REDIRECT", justification = "TODO needs triage")
         public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
             // Force root requests to the setup wizard
             if (request instanceof HttpServletRequest && !Jenkins.get().getInstallState().isSetupComplete()) {

pom.xml

@@ -84,8 +84,8 @@ THE SOFTWARE.
     <project.patchManagement.url>https://api.github.com</project.patchManagement.url>
     <patch.tracker.serverId>jenkins-jira</patch.tracker.serverId>
 
-    <animal.sniffer.skip>${skipTests}</animal.sniffer.skip>
-    <java.level>8</java.level>
+    <animal.sniffer.skip>true</animal.sniffer.skip>
+    <java.level>11</java.level>
 
     <changelog.url>https://www.jenkins.io/changelog</changelog.url>
 
@@ -536,7 +536,7 @@ THE SOFTWARE.
           <arguments>-P release,sign</arguments>
           <!-- work around for a bug in javadoc plugin that causes the release to fail. see MRELEASE-271 -->
           <preparationGoals>clean install</preparationGoals>
-          <goals>-DskipTests -Danimal.sniffer.skip=false javadoc:javadoc deploy</goals>
+          <goals>-DskipTests javadoc:javadoc deploy</goals>
           <pushChanges>false</pushChanges>
           <localCheckout>true</localCheckout>
           <tagNameFormat>jenkins-@{project.version}</tagNameFormat>
@@ -581,8 +581,7 @@ THE SOFTWARE.
         <artifactId>maven-compiler-plugin</artifactId>
         <!-- Version specified in parent POM -->
         <configuration>
-          <source>1.${java.level}</source>
-          <target>1.${java.level}</target>
+          <release>${java.level}</release>
           <!-- default reuseCreated is more performant
           feel free to uncomment if you have any issues on your platform
           <compilerReuseStrategy>alwaysNew</compilerReuseStrategy>
@@ -743,22 +742,5 @@ THE SOFTWARE.
         <failIfNoTests>false</failIfNoTests>
       </properties>
     </profile>
-    <profile>
-      <id>jdk11</id>
-      <properties>
-        <!-- TODO: https://issues.jenkins.io/browse/JENKINS-53788 (JDK11 issue on CI) -->
-        <doclint>none</doclint>
-        <maven.javadoc.skip>true</maven.javadoc.skip>
-        <!-- release is needed for reliable cross compilation. It is supported
-        starting JDK 9, but as the only earlier version we support is 8, it would
-        be either compiled by javac from 8 or one from a newer compiler that
-        correctly handle the release flag. This will replace both source and target
-        once we drop support for JDK 8 that only recognize source and target. -->
-        <maven.compiler.release>${java.level}</maven.compiler.release>
-      </properties>
-      <activation>
-        <jdk>11</jdk>
-      </activation>
-    </profile>
   </profiles>
 </project>

src/spotbugs/spotbugs-excludes.xml

@@ -364,6 +364,7 @@
           <Class name="hudson.model.AsyncAperiodicWork"/>
           <Class name="hudson.model.AsyncPeriodicWork"/>
           <Class name="hudson.model.Computer"/>
+          <Class name="hudson.model.Descriptor"/>
           <Class name="hudson.model.DirectoryBrowserSupport$IsAbsolute"/>
           <Class name="hudson.model.DownloadService$Downloadable"/>
           <Class name="hudson.model.FileParameterValue"/>
@@ -399,6 +400,7 @@
           <Class name="hudson.util.io.RewindableRotatingFileOutputStream"/>
           <Class name="hudson.util.IOUtils"/>
           <Class name="hudson.util.jna.Kernel32Utils"/>
+          <Class name="hudson.util.ProcessTree$UnixProcess"/>
           <Class name="hudson.WebAppMain"/>
           <Class name="jenkins.diagnosis.HsErrPidList"/>
           <Class name="jenkins.fingerprints.FileFingerprintStorage"/>
@@ -417,6 +419,7 @@
           <Class name="jenkins.security.s2m.ConfigDirectory"/>
           <Class name="jenkins.security.stapler.StaplerDispatchValidator$ValidatorCache"/>
           <Class name="jenkins.security.stapler.StaticRoutingDecisionProvider"/>
+          <Class name="jenkins.slaves.restarter.UnixSlaveRestarter"/>
           <Class name="jenkins.SoloFilePathFilter"/>
           <Class name="jenkins.util.groovy.GroovyHookScript"/>
           <Class name="jenkins.util.io.FileBoolean"/>