Adapt plugin for Java 21

Jenkinsfile

@@ -8,9 +8,10 @@ buildPlugin(
   useContainerAgent: true,
   // Show failures on all configurations
   failFast: false,
-  // Test Java 11 and Java 17
+  // Test Java 11, 17, and 21
   configurations: [
     [platform: 'linux',   jdk: '17'], // Linux first for coverage report on ci.jenkins.io
+    [platform: 'linux',   jdk: '21', jenkins: '2.414'],
     [platform: 'windows', jdk: '11'],
   ]
 )

src/main/java/org/jenkinsci/plugins/schedulebuild/ScheduleBuildGlobalConfiguration.java

@@ -4,9 +4,17 @@
 import hudson.util.FormValidation;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
 import java.util.Date;
 import java.util.Locale;
 import java.util.TimeZone;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import jenkins.model.GlobalConfiguration;
 import jenkins.model.Jenkins;
 import net.sf.json.JSONObject;
@@ -18,9 +26,27 @@
 @Extension
 @Symbol("scheduleBuild")
 public class ScheduleBuildGlobalConfiguration extends GlobalConfiguration {
+    // defaultScheduleTime is a misuse of a Date object.  Used for the
+    // time portion (hours, minutes, seconds, etc.) while the date
+    // portion is ignored.
     private Date defaultScheduleTime;
     private String timeZone;
 
+    private static final Logger LOGGER = Logger.getLogger(ScheduleBuildGlobalConfiguration.class.getName());
+
+    private static final LocalDate EPOCH = LocalDate.of(1970, 1, 1);
+    private static final ZoneId ZONE = ZoneId.systemDefault();
+    private static final DateTimeFormatter[] FORMATTERS = {
+        DateTimeFormatter.ofPattern("H:m:s a"), // Original format required by DateFormat
+        DateTimeFormatter.ofPattern("h:m:s a"),
+        DateTimeFormatter.ofPattern("H:m a"),
+        DateTimeFormatter.ofPattern("h:m a"),
+        DateTimeFormatter.ofPattern("H:m:s"),
+        DateTimeFormatter.ofPattern("h:m:s"),
+        DateTimeFormatter.ofPattern("H:m"),
+        DateTimeFormatter.ofPattern("h:m"),
+    };
+
     @DataBoundConstructor
     public ScheduleBuildGlobalConfiguration() {
         this.defaultScheduleTime = new Date(0, 0, 0, 22, 0);
@@ -34,7 +60,29 @@ public String getDefaultScheduleTime() {
 
     @DataBoundSetter
     public void setDefaultScheduleTime(String defaultScheduleTime) throws ParseException {
-        this.defaultScheduleTime = getTimeFormat().parse(defaultScheduleTime);
+        try {
+            this.defaultScheduleTime = getTimeFormat().parse(defaultScheduleTime);
+        } catch (ParseException parseException) {
+            /* Try each of the formatters with the user provided data, return first success */
+            /* Java 21 changed DateFormat to not accept strings with only a time component */
+            /* DateTimeFormatter parsing allows Java 11, 17, and 21 to accept several time string formats */
+            for (DateTimeFormatter formatter : FORMATTERS) {
+                try {
+                    LocalTime localTime = LocalTime.parse(defaultScheduleTime, formatter);
+                    Instant instant = localTime.atDate(EPOCH).atZone(ZONE).toInstant();
+                    this.defaultScheduleTime = Date.from(instant);
+                    // LOGGER.log(Level.FINEST, "Parsed '" + defaultScheduleTime + "' with formatter " + formatter);
+                    return;
+                } catch (DateTimeParseException dtex) {
+                    LOGGER.log(
+                            Level.FINE,
+                            "Did not parse '" + defaultScheduleTime + "' with formatter " + formatter,
+                            dtex);
+                }
+            }
+            /* Throw the original exception if no match is found */
+            throw parseException;
+        }
     }
 
     public String getTimeZone() {

src/test/java/org/jenkinsci/plugins/schedulebuild/ScheduleBuildActionTest.java

@@ -3,6 +3,7 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.endsWith;
+import static org.hamcrest.Matchers.matchesPattern;
 import static org.hamcrest.Matchers.nullValue;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
@@ -89,7 +90,7 @@ public void testSchedule() throws Exception {
 
     @Test
     public void testGetDefaultDate() throws Exception {
-        assertThat(scheduleBuildAction.getDefaultDate(), endsWith(" 10:00:00 PM"));
+        assertThat(scheduleBuildAction.getDefaultDate(), matchesPattern(".* 10:00:00\\hPM"));
     }
 
     @Test

src/test/java/org/jenkinsci/plugins/schedulebuild/ScheduleBuildGlobalConfigurationTest.java

@@ -2,6 +2,7 @@
 
 import static org.hamcrest.CoreMatchers.*;
 import static org.hamcrest.MatcherAssert.*;
+import static org.hamcrest.Matchers.matchesPattern;
 import static org.junit.Assert.assertThrows;
 
 import java.time.ZoneId;
@@ -30,7 +31,7 @@ public void setUp() {
     @Test
     public void configRoundTripTestNoChanges() throws Exception {
         assertThat(globalConfig, is(not(nullValue())));
-        assertThat(globalConfig.getDefaultScheduleTime(), is("10:00:00 PM"));
+        assertThat(globalConfig.getDefaultScheduleTime(), matchesPattern("10:00:00\\hPM"));
         assertThat(globalConfig.getTimeZone(), is(TimeZone.getDefault().getID()));
 
         // Submit the global configuration page with no changes
@@ -39,7 +40,7 @@ public void configRoundTripTestNoChanges() throws Exception {
         ScheduleBuildGlobalConfiguration newGlobalConfig =
                 GlobalConfiguration.all().getInstance(ScheduleBuildGlobalConfiguration.class);
         assertThat(newGlobalConfig, is(not(nullValue())));
-        assertThat(newGlobalConfig.getDefaultScheduleTime(), is("10:00:00 PM"));
+        assertThat(newGlobalConfig.getDefaultScheduleTime(), matchesPattern("10:00:00\\hPM"));
         assertThat(newGlobalConfig.getTimeZone(), is(TimeZone.getDefault().getID()));
     }
 
@@ -57,7 +58,25 @@ public void configRoundTripTestWithChanges() throws Exception {
         ScheduleBuildGlobalConfiguration newGlobalConfig =
                 GlobalConfiguration.all().getInstance(ScheduleBuildGlobalConfiguration.class);
         assertThat(newGlobalConfig, is(not(nullValue())));
-        assertThat(newGlobalConfig.getDefaultScheduleTime(), is(newScheduleTime));
+        assertThat(newGlobalConfig.getDefaultScheduleTime(), matchesPattern("1:23:45\\hPM"));
+        assertThat(newGlobalConfig.getTimeZone(), is(newTimeZone));
+    }
+
+    @Test
+    public void configRoundTripTestWithChangesSimpleTime() throws Exception {
+        // Adjust global configuration values
+        String newScheduleTime = "2:34";
+        String newTimeZone = "Europe/Rome";
+        globalConfig.setDefaultScheduleTime(newScheduleTime);
+        globalConfig.setTimeZone(newTimeZone);
+
+        // Submit the global configuration page, will not change adjusted values
+        j.configRoundtrip();
+
+        ScheduleBuildGlobalConfiguration newGlobalConfig =
+                GlobalConfiguration.all().getInstance(ScheduleBuildGlobalConfiguration.class);
+        assertThat(newGlobalConfig, is(not(nullValue())));
+        assertThat(newGlobalConfig.getDefaultScheduleTime(), matchesPattern("2:34:00\\hAM"));
         assertThat(newGlobalConfig.getTimeZone(), is(newTimeZone));
     }
 
@@ -79,14 +98,14 @@ public void testDoCheckTimeZone() throws Exception {
 
     @Test
     public void testGetDefaultScheduleTime() {
-        assertThat(globalConfig.getDefaultScheduleTime(), is("10:00:00 PM"));
+        assertThat(globalConfig.getDefaultScheduleTime(), matchesPattern("10:00:00\\hPM"));
     }
 
     @Test
     public void testSetDefaultScheduleTime() throws Exception {
         String defaultScheduleTime = "12:34:56 PM";
         globalConfig.setDefaultScheduleTime(defaultScheduleTime);
-        assertThat(globalConfig.getDefaultScheduleTime(), is(defaultScheduleTime));
+        assertThat(globalConfig.getDefaultScheduleTime(), matchesPattern("12:34:56\\hPM"));
     }
 
     @Test

src/test/resources/org/jenkinsci/plugins/schedulebuild/scheduleBuild-all-fields.yaml

@@ -1,4 +1,4 @@
 unclassified:
   scheduleBuild:
-    defaultScheduleTime: "12:34:56 AM"
+    defaultScheduleTime: "12:34:56"
     timeZone: "Europe/Rome"