Configure Guice classloading for Java 21+ compatibility

Add -Dguice_custom_class_loading=CHILD to avoid sun.misc.Unsafe
warnings on Java 21+. This prevents "terminally deprecated method"
warnings from Guice 5.1.0's HiddenClassDefiner.

Changes:
- Add flag to Eclipse launch configurations (3 files)
- Add flag to product definitions (languageServer, syntaxServer)
- Add flag to tycho-surefire test configuration

Based on Maven fix: apache/maven#10992
Resolves sun.misc.Unsafe::staticFieldBase deprecation warnings

Author: claude

GUICE_UPGRADE_ANALYSIS.md

@@ -36,7 +36,7 @@
     <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
     <stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-os ${target.os} -ws ${target.ws} -arch ${target.arch} -nl ${target.nl} -consoleLog"/>
     <stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
-    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Djava.import.generatesMetadataFilesAtProjectRoot=false"/>
+    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Dguice_custom_class_loading=CHILD -Djava.import.generatesMetadataFilesAtProjectRoot=false"/>
     <stringAttribute key="pde.version" value="3.3"/>
     <stringAttribute key="product" value="org.eclipse.sdk.ide"/>
     <setAttribute key="selected_features"/>

launch/jdt.ls.remote.server.launch

@@ -37,7 +37,7 @@
     <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
     <stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-os ${target.os} -ws ${target.ws} -arch ${target.arch} -nl ${target.nl} -consoleLog"/>
     <stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
-    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Djava.import.generatesMetadataFilesAtProjectRoot=false"/>
+    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Dguice_custom_class_loading=CHILD -Djava.import.generatesMetadataFilesAtProjectRoot=false"/>
     <stringAttribute key="pde.version" value="3.3"/>
     <stringAttribute key="product" value="org.eclipse.sdk.ide"/>
     <setAttribute key="selected_features"/>

launch/jdt.ls.socket-stream.launch

@@ -39,7 +39,7 @@
     <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
     <stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-os ${target.os} -ws ${target.ws} -arch ${target.arch} -nl ${target.nl} -consoleLog"/>
     <stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
-    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Djava.import.generatesMetadataFilesAtProjectRoot=false"/>
+    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Dguice_custom_class_loading=CHILD -Djava.import.generatesMetadataFilesAtProjectRoot=false"/>
     <stringAttribute key="pde.version" value="3.3"/>
     <stringAttribute key="product" value="org.eclipse.sdk.ide"/>
     <setAttribute key="selected_features"/>

launch/jdt.ls.socket-stream.syntaxserver.launch

@@ -7,6 +7,8 @@
    </configIni>
 
    <launcherArgs>
+      <vmArgs>-Dguice_custom_class_loading=CHILD
+      </vmArgs>
       <vmArgsMac>-XstartOnFirstThread -Dorg.eclipse.swt.internal.carbon.smallFonts
       </vmArgsMac>
    </launcherArgs>

org.eclipse.jdt.ls.product/languageServer.product

@@ -7,6 +7,8 @@
    </configIni>
 
    <launcherArgs>
+      <vmArgs>-Dguice_custom_class_loading=CHILD
+      </vmArgs>
       <vmArgsMac>-XstartOnFirstThread -Dorg.eclipse.swt.internal.carbon.smallFonts
       </vmArgsMac>
    </launcherArgs>

org.eclipse.jdt.ls.product/syntaxServer.product

@@ -48,7 +48,7 @@
 					<artifactId>tycho-surefire-plugin</artifactId>
 					<version>${tycho-version}</version>
 					<configuration>
-						<argLine>${tycho.testArgLine} ${os.testArgs} "${lombokArgs}"</argLine>
+						<argLine>-Dguice_custom_class_loading=CHILD ${tycho.testArgLine} ${os.testArgs} "${lombokArgs}"</argLine>
 						<runOrder>random</runOrder>
 						<providerProperties>
 							<excludegroups>org.eclipse.jdt.ls.tests.Unstable</excludegroups>