chore!: set Java 21 as baseline (#8101)

* chore!: set Java 21 as baseline

* set Java version through maven.compiler.release

* specify maven-compiler-plugin version in pom.xml

* move maven-compiler-plugin to pluginManagement

* fix tests by supporting narrow no-break space in formatted dates

* format code

* add @NotThreadSafe to MessageListTest

* format code

Author: vursen

pom.xml

@@ -71,8 +71,7 @@
     <properties>
         <flow.version>25.0-SNAPSHOT</flow.version>
         <testbench.version>10.0.0-alpha4</testbench.version>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
+        <maven.compiler.release>21</maven.compiler.release>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <jetty.version>12.0.23</jetty.version>
@@ -291,6 +290,11 @@
     <build>
         <pluginManagement>
             <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.14.1</version>
+                </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-source-plugin</artifactId>

vaadin-grid-flow-parent/vaadin-grid-flow-integration-tests/src/test/java/com/vaadin/flow/component/grid/it/AddingColumnsIT.java

@@ -75,10 +75,10 @@ public void gridRendered_addColumnWithLocalDateTimeRenderer_cellsRendered() {
         // JDK16 adds extra comma after year in en_US
         Assert.assertTrue(
                 TestHelper.stripComments(grid.getCell(0, 0).getInnerHTML())
-                        .matches("January 1, 1980,? 1:20[ \\u00A0]AM"));
+                        .matches("January 1, 1980,? 1:20[ \\u00A0\\u202F]AM"));
         Assert.assertTrue(
                 TestHelper.stripComments(grid.getCell(1, 0).getInnerHTML())
-                        .matches("January 1, 1980,? 1:30[ \\u00A0]AM"));
+                        .matches("January 1, 1980,? 1:30[ \\u00A0\\u202F]AM"));
     }
 
     @Test

vaadin-grid-flow-parent/vaadin-grid-flow-integration-tests/src/test/java/com/vaadin/flow/component/grid/it/GridViewUsingRenderersIT.java

@@ -47,8 +47,8 @@ public void init() {
     public void basicRenderers_rowsAreRenderedAsExpected() {
         Assert.assertEquals("Item 1", grid.getCell(0, 0).getText());
         Assert.assertEquals("$ 73.10", grid.getCell(0, 1).getText());
-        Assert.assertTrue(
-                grid.getCell(0, 2).getText().matches("1/10/18,? 11:43:59 AM"));
+        Assert.assertTrue(grid.getCell(0, 2).getText()
+                .matches("1/10/18,? 11:43:59[ \\u00A0\\u202F]AM"));
         Assert.assertEquals("Jan 11, 2018", grid.getCell(0, 3).getText());
         assertRendereredContent("<span>$$$</span>",
                 TestHelper.stripComments(grid.getCell(0, 4).getInnerHTML()));
@@ -57,8 +57,8 @@ public void basicRenderers_rowsAreRenderedAsExpected() {
 
         Assert.assertEquals("Item 2", grid.getCell(1, 0).getText());
         Assert.assertEquals("$ 24.05", grid.getCell(1, 1).getText());
-        Assert.assertTrue(
-                grid.getCell(1, 2).getText().matches("1/10/18,? 11:07:31 AM"));
+        Assert.assertTrue(grid.getCell(1, 2).getText()
+                .matches("1/10/18,? 11:07:31[ \\u00A0\\u202F]AM"));
         Assert.assertEquals("Jan 24, 2018", grid.getCell(1, 3).getText());
         assertRendereredContent("<span>$</span>",
                 TestHelper.stripComments(grid.getCell(1, 4).getInnerHTML()));

vaadin-messages-flow-parent/vaadin-messages-flow/pom.xml

@@ -35,6 +35,12 @@
             <groupId>jakarta.servlet</groupId>
             <artifactId>jakarta.servlet-api</artifactId>
         </dependency>
+        <dependency>
+            <groupId>net.jcip</groupId>
+            <artifactId>jcip-annotations</artifactId>
+            <version>1.0</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>

vaadin-messages-flow-parent/vaadin-messages-flow/src/test/java/com/vaadin/flow/component/messages/tests/MessageListTest.java

@@ -31,8 +31,10 @@
 import com.vaadin.flow.server.streams.DownloadHandler;
 import com.vaadin.flow.server.streams.DownloadResponse;
 
+import net.jcip.annotations.NotThreadSafe;
 import tools.jackson.databind.JsonNode;
 
+@NotThreadSafe
 public class MessageListTest {
 
     private MessageList messageList;

vaadin-virtual-list-flow-parent/vaadin-virtual-list-flow-integration-tests/src/test/java/com/vaadin/flow/component/virtuallist/tests/VirtualListIT.java

@@ -350,11 +350,11 @@ public void localDateTimeRenderer() {
 
         // JDK16 adds extra comma after year in en_US
         Assert.assertTrue(items.get(0).getText()
-                .matches("January 1, 2001,? 1:01[ \\u00A0]AM"));
+                .matches("January 1, 2001,? 1:01[ \\u00A0\\u202F]AM"));
         Assert.assertTrue(items.get(1).getText()
-                .matches("February 2, 2002,? 2:02[ \\u00A0]AM"));
+                .matches("February 2, 2002,? 2:02[ \\u00A0\\u202F]AM"));
         Assert.assertTrue(items.get(2).getText()
-                .matches("March 3, 2003,? 3:03[ \\u00A0]AM"));
+                .matches("March 3, 2003,? 3:03[ \\u00A0\\u202F]AM"));
     }
 
     @Test