Cleanup deprecation

src/main/java/jenkins/plugins/slack/ActiveNotifier.java

@@ -230,7 +230,7 @@ String getCommitList(AbstractBuild r) {
             }
             String upProjectName = c.getUpstreamProject();
             int buildNumber = c.getUpstreamBuild();
-            AbstractProject project = Jenkins.getActiveInstance().getItemByFullName(upProjectName, AbstractProject.class);
+            AbstractProject project = Jenkins.get().getItemByFullName(upProjectName, AbstractProject.class);
             if (project != null) {
                 AbstractBuild upBuild = project.getBuildByNumber(buildNumber);
                 return getCommitList(upBuild);

src/main/java/jenkins/plugins/slack/SlackNotifier.java

@@ -550,7 +550,7 @@ public ListBoxModel doFillCommitInfoChoiceItems() {
 
         public ListBoxModel doFillTokenCredentialIdItems(@AncestorInPath Item context) {
 
-            Jenkins jenkins = Jenkins.getActiveInstance();
+            Jenkins jenkins = Jenkins.get();
 
             if(context == null && !jenkins.hasPermission(Jenkins.ADMINISTER) ||
                     context != null && !context.hasPermission(Item.EXTENDED_READ)) {
@@ -829,7 +829,7 @@ public void onLoaded() {
 
             ItemConfigMigrator migrator = new ItemConfigMigrator();
 
-            Jenkins jenkins = Jenkins.getActiveInstance();
+            Jenkins jenkins = Jenkins.get();
 
             List<Item> items = jenkins.getAllItems();
             if (null != items) {

src/main/java/jenkins/plugins/slack/StandardSlackService.java

@@ -195,7 +195,7 @@ private String getTokenToUse() {
     }
 
     private StringCredentials lookupCredentials(String credentialId) {
-        List<StringCredentials> credentials = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(StringCredentials.class, Jenkins.getInstance(), ACL.SYSTEM, Collections.emptyList());
+        List<StringCredentials> credentials = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(StringCredentials.class, Jenkins.get(), ACL.SYSTEM, Collections.emptyList());
         CredentialsMatcher matcher = CredentialsMatchers.withId(credentialId);
         return CredentialsMatchers.firstOrNull(credentials, matcher);
     }

src/main/java/jenkins/plugins/slack/webhook/GetProjectLogCommand.java

@@ -25,7 +25,7 @@ public SlackTextMessage execute(String... args) {
         List<String> log;
 
         try (ACLContext ignored = ACL.as(ACL.SYSTEM)) {
-            Project project = Jenkins.getActiveInstance().getItemByFullName(projectName, Project.class);
+            Project project = Jenkins.get().getItemByFullName(projectName, Project.class);
 
             if (project == null) {
                 return new SlackTextMessage("Could not find project (" + projectName + ")\n");

src/main/java/jenkins/plugins/slack/webhook/ListProjectsCommand.java

@@ -25,7 +25,7 @@ public ListProjectsCommand(SlackPostData data) {
     public SlackTextMessage execute(String... args) {
         List<AbstractProject> jobs;
         try (ACLContext ignored = ACL.as(ACL.SYSTEM)) {
-            Jenkins jenkins = Jenkins.getActiveInstance();
+            Jenkins jenkins = Jenkins.get();
 
             jobs = jenkins.getAllItems(AbstractProject.class);
         }

src/main/java/jenkins/plugins/slack/webhook/ScheduleJobCommand.java

@@ -19,7 +19,7 @@ public SlackTextMessage execute(String... args) {
         String projectName = args[0];
 
         try (ACLContext ignored = ACL.as(ACL.SYSTEM)) {
-            Jenkins jenkins = Jenkins.getActiveInstance();
+            Jenkins jenkins = Jenkins.get();
 
             Project project =
                     jenkins.getItemByFullName(projectName, Project.class);

src/main/java/jenkins/plugins/slack/workflow/SlackSendStep.java

@@ -2,11 +2,13 @@
 
 import com.cloudbees.plugins.credentials.common.StandardListBoxModel;
 import com.cloudbees.plugins.credentials.domains.HostnameRequirement;
+import com.google.common.collect.ImmutableSet;
 import hudson.AbortException;
 import hudson.Extension;
 import hudson.Util;
 import hudson.model.Item;
 import hudson.model.Project;
+import hudson.model.Run;
 import hudson.model.TaskListener;
 import hudson.security.ACL;
 import hudson.util.FormValidation;
@@ -22,24 +24,26 @@
 import net.sf.json.JSONObject;
 import net.sf.json.groovy.JsonSlurper;
 import org.jenkinsci.plugins.plaincredentials.StringCredentials;
-import org.jenkinsci.plugins.workflow.steps.AbstractStepDescriptorImpl;
-import org.jenkinsci.plugins.workflow.steps.AbstractStepImpl;
-import org.jenkinsci.plugins.workflow.steps.AbstractSynchronousNonBlockingStepExecution;
-import org.jenkinsci.plugins.workflow.steps.StepContextParameter;
+import org.jenkinsci.plugins.workflow.steps.Step;
+import org.jenkinsci.plugins.workflow.steps.StepContext;
+import org.jenkinsci.plugins.workflow.steps.StepDescriptor;
+import org.jenkinsci.plugins.workflow.steps.StepExecution;
+import org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution;
 import org.kohsuke.stapler.AncestorInPath;
 import org.kohsuke.stapler.DataBoundConstructor;
 import org.kohsuke.stapler.DataBoundSetter;
 import org.kohsuke.stapler.QueryParameter;
 
+import java.util.Objects;
+import java.util.Set;
 import javax.annotation.Nonnull;
-import javax.inject.Inject;
 
 import static com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials;
 
 /**
  * Workflow step to send a Slack channel notification.
  */
-public class SlackSendStep extends AbstractStepImpl {
+public class SlackSendStep extends Step {
 
     private String message;
     private String color;
@@ -161,11 +165,17 @@ public void setReplyBroadcast(boolean replyBroadcast) {
     public SlackSendStep() {
     }
 
+    @Override
+    public StepExecution start(StepContext context) {
+        return new SlackSendStepExecution(this, context);
+    }
+
     @Extension
-    public static class DescriptorImpl extends AbstractStepDescriptorImpl {
+    public static class DescriptorImpl extends StepDescriptor {
 
-        public DescriptorImpl() {
-            super(SlackSendStepExecution.class);
+        @Override
+        public Set<? extends Class<?>> getRequiredContext() {
+            return ImmutableSet.of(Run.class, TaskListener.class);
         }
 
         @Override
@@ -181,7 +191,7 @@ public String getDisplayName() {
 
         public ListBoxModel doFillTokenCredentialIdItems(@AncestorInPath Project project) {
 
-            Jenkins jenkins = Jenkins.getActiveInstance();
+            Jenkins jenkins = Jenkins.get();
 
             if (project == null && !jenkins.hasPermission(Jenkins.ADMINISTER) ||
                     project != null && !project.hasPermission(Item.EXTENDED_READ)) {
@@ -206,20 +216,21 @@ public FormValidation doCheckToken(@QueryParameter String value) {
         }
     }
 
-    public static class SlackSendStepExecution extends AbstractSynchronousNonBlockingStepExecution<SlackResponse> {
+    public static class SlackSendStepExecution extends SynchronousNonBlockingStepExecution<SlackResponse> {
 
         private static final long serialVersionUID = 1L;
 
-        @Inject
-        transient SlackSendStep step;
+        private transient final SlackSendStep step;
 
-        @StepContextParameter
-        transient TaskListener listener;
+        SlackSendStepExecution(SlackSendStep step, StepContext context) {
+            super(context);
+            this.step = step;
+        }
 
         @Override
         protected SlackResponse run() throws Exception {
 
-            Jenkins jenkins = Jenkins.getActiveInstance();
+            Jenkins jenkins = Jenkins.get();
 
             SlackNotifier.DescriptorImpl slackDesc = jenkins.getDescriptorByType(SlackNotifier.DescriptorImpl.class);
 
@@ -232,6 +243,9 @@ protected SlackResponse run() throws Exception {
             String channel = step.channel != null ? step.channel : slackDesc.getRoom();
             String color = step.color != null ? step.color : "";
 
+            TaskListener listener = getContext().get(TaskListener.class);
+            Objects.requireNonNull(listener, "Listener is mandatory here");
+
             listener.getLogger().println(Messages.SlackSendStepValues(
                     defaultIfEmpty(baseUrl), defaultIfEmpty(teamDomain), channel, defaultIfEmpty(color), botUser,
                     defaultIfEmpty(tokenCredentialId))