Java Upgrade to LTS 21

.classpath

@@ -25,7 +25,7 @@
 			<attribute name="owner.project.facets" value="jst.utility"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-16">
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21">
 		<attributes>
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>

.github/workflows/maven-test.yml

@@ -12,13 +12,13 @@ jobs:
 
     strategy:
       matrix:
-        java: [ 17, 21 ]
+        java: [ 21, 23 ]
 
     steps:
       - uses: actions/checkout@v2
 
       - name: Set up JDK for java ${{matrix.java}}
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           java-version: ${{matrix.java}}
           distribution: 'temurin'

pom.xml

@@ -430,12 +430,11 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.1</version>
+                <version>3.14.1</version>
                 <configuration>
                     <verbose>true</verbose>
                     <fork>true</fork>
-                    <source>16</source>
-                    <target>16</target>
+          <release>21</release>
                 </configuration>
             </plugin>
             <plugin>

src/main/java/edu/harvard/mcz/imagecapture/ImageCaptureApp.java

@@ -23,21 +23,24 @@
  */
 package edu.harvard.mcz.imagecapture;
 
+import java.awt.Cursor;
+import java.io.IOException;
+import java.util.Properties;
+
+import javax.swing.JOptionPane;
+import javax.swing.UIManager;
+import javax.swing.UnsupportedLookAndFeelException;
+
+import org.hibernate.HibernateException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import edu.harvard.mcz.imagecapture.entity.Specimen;
 import edu.harvard.mcz.imagecapture.exceptions.ConnectionException;
 import edu.harvard.mcz.imagecapture.lifecycle.AllowedVersionLifeCycle;
 import edu.harvard.mcz.imagecapture.lifecycle.SpecimenLifeCycle;
 import edu.harvard.mcz.imagecapture.ui.frame.MainFrame;
 import edu.harvard.mcz.imagecapture.ui.tablemodel.RunnableJobTableModel;
-import org.hibernate.HibernateException;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import javax.swing.*;
-import java.awt.*;
-import java.io.IOException;
-import java.util.Locale;
-import java.util.Properties;
 
 /**
  * Main entry point for user interface of ImageCapture Java Application. Creates
@@ -55,20 +58,20 @@ public class ImageCaptureApp {
     public static final String APP_COPYRIGHT =
             "Copyright © 2009-2017 President and Fellows of Harvard College";
     public static final String APP_LICENSE =
-            "This program is free software; you can redistribute it and/or modify \n "
-                    + "it under the terms of Version 2 of the GNU General Public License \n"
-                    + "as published by the Free Software Foundation"
-                    + " \n "
-                    + "This program is distributed in the hope that it will be useful,\n "
-                    + "but WITHOUT ANY WARRANTY; without even the implied warranty of\n "
-                    + "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n "
-                    + "GNU General Public License for more details.\n "
-                    + "\n "
-                    +
-                    "You should have received a copy of the GNU General Public License along\n "
-                    +
-                    "with this program; if not, write to the Free Software Foundation, Inc.,\n "
-                    + "51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.\n ";
+            """
+            This program is free software; you can redistribute it and/or modify
+            it under the terms of Version 2 of the GNU General Public License
+            as published by the Free Software Foundation.
+
+            This program is distributed in the hope that it will be useful,
+            but WITHOUT ANY WARRANTY; without even the implied warranty of
+            MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+            GNU General Public License for more details.
+
+            You should have received a copy of the GNU General Public License along
+            with this program; if not, write to the Free Software Foundation, Inc.,
+            51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+             """;
     public static final String APP_CONTRIBUTORS =
             "Brendan Haley, Linda Ford, Rodney Eastwood, Paul J. Morris, Tim Bernhard.";
     public static final String APP_LIBRARIES =