Use Multi-Release Type for Caller implementation

The current implementation for Java 1.8 is rather complex because of
only raw string info.

With Java 9+ we can use StackWalker to perform faster and easier, to
still retain compatibility with Java 1.8 we use a Multi-Release type
here to use that implementation on any 9+ JVM.

Author: laeubi

ui/org.eclipse.pde.junit.runtime/.classpath

@@ -1,7 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-9">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="src" path="src9">
+		<attributes>
+			<attribute name="release" value="9"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

ui/org.eclipse.pde.junit.runtime/.settings/org.eclipse.jdt.core.prefs

@@ -8,6 +8,7 @@ org.eclipse.jdt.core.circularClasspath=error
 org.eclipse.jdt.core.classpath.exclusionPatterns=enabled
 org.eclipse.jdt.core.classpath.multipleOutputLocations=enabled
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate
 org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
 org.eclipse.jdt.core.compiler.compliance=1.8

ui/org.eclipse.pde.junit.runtime/.settings/org.eclipse.pde.prefs

@@ -1,6 +1,6 @@
 compilers.f.unresolved-features=1
 compilers.f.unresolved-plugins=1
-compilers.incompatible-environment=0
+compilers.incompatible-environment=2
 compilers.p.build=1
 compilers.p.build.bin.includes=1
 compilers.p.build.encodings=2
@@ -12,14 +12,18 @@ compilers.p.build.source.library=1
 compilers.p.build.src.includes=1
 compilers.p.deprecated=1
 compilers.p.discouraged-class=1
+compilers.p.exec-env-too-low=2
+compilers.p.ignored-resource-protocols=
 compilers.p.internal=1
 compilers.p.matching-pom-version=0
 compilers.p.missing-packages=0
 compilers.p.missing-version-export-package=2
 compilers.p.missing-version-import-package=2
 compilers.p.missing-version-require-bundle=2
 compilers.p.no-required-att=0
+compilers.p.no.automatic.module=1
 compilers.p.not-externalized-att=1
+compilers.p.service.component.without.lazyactivation=1
 compilers.p.unknown-attribute=1
 compilers.p.unknown-class=1
 compilers.p.unknown-element=1

ui/org.eclipse.pde.junit.runtime/META-INF/MANIFEST.MF

@@ -14,3 +14,4 @@ Bundle-ActivationPolicy: lazy
 Import-Package: org.eclipse.ui.testing;resolution:=optional
 DynamicImport-Package: org.junit.platform.engine;version="[1.14.0,2.0.0)"
 Automatic-Module-Name: org.eclipse.pde.junit.runtime
+Multi-Release: true

ui/org.eclipse.pde.junit.runtime/src/org/eclipse/pde/internal/junit/runtime/Caller.java

@@ -24,7 +24,6 @@
 
 /**
  * Default implementation used with Java 1.8
- * TODO provide MR variant using stack walker, currently blocked by JDT bug ...
  */
 public class Caller {
 

ui/org.eclipse.pde.junit.runtime/src9/org/eclipse/pde/internal/junit/runtime/Caller.java

@@ -0,0 +1,33 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Christoph Läubrich and others.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Christoph Läubrich - initial API and implementation
+ *
+ */
+package org.eclipse.pde.internal.junit.runtime;
+
+import java.util.Objects;
+
+import org.osgi.framework.Bundle;
+import org.osgi.framework.FrameworkUtil;
+
+/**
+ * Release specific implementation that using stack walker
+ */
+public class Caller {
+
+	private static final StackWalker WALKER = StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
+	private static final Bundle LOADER_BUNDLE = FrameworkUtil.getBundle(SPIBundleClassLoader.class);
+
+	static Bundle getBundle(int junitVersion) {
+		return WALKER.walk(stream -> stream.map(sf -> FrameworkUtil.getBundle(sf.getDeclaringClass())).filter(Objects::nonNull).filter(b -> b != LOADER_BUNDLE).findFirst().orElse(null));
+	}
+
+}