Add Java projects to classpath container org.eclipse.pde.core.externaJavaSearch

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/SearchablePluginsManager.java

@@ -183,10 +183,16 @@ public IClasspathEntry[] computeContainerClasspathEntries() {
 		for (String id : plugins) {
 			ModelEntry entry = PluginRegistry.findEntry(id);
 			if (entry != null) {
-				boolean addModel = Arrays.stream(entry.getWorkspaceModels())
+				List<IProject> javaProjects = Arrays.stream(entry.getWorkspaceModels())
 						.map(IPluginModelBase::getUnderlyingResource).map(IResource::getProject)
-						.noneMatch(PluginProject::isJavaProject);
+						.filter(PluginProject::isJavaProject).collect(Collectors.toList());
+				boolean addModel = javaProjects.isEmpty();
 				if (!addModel) {
+					for (IProject project : javaProjects) {
+						IPath path = project.getFullPath();
+						IClasspathEntry projectEntry = JavaCore.newProjectEntry(path);
+						result.add(projectEntry);
+					}
 					continue;
 				}
 				IPluginModelBase[] models = entry.getExternalModels();

ui/org.eclipse.pde.ui.tests/src/org/eclipse/pde/core/tests/internal/classpath/ExternalJavaSearchClasspathContainerTests.java

@@ -0,0 +1,138 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Simeon Andreev 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:
+ *     Simeon Andreev - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.pde.core.tests.internal.classpath;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.resources.IWorkspaceRoot;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.NullProgressMonitor;
+import org.eclipse.jdt.core.IJavaElement;
+import org.eclipse.jdt.core.IJavaProject;
+import org.eclipse.jdt.core.JavaCore;
+import org.eclipse.jdt.core.JavaModelException;
+import org.eclipse.jdt.core.search.IJavaSearchConstants;
+import org.eclipse.jdt.core.search.SearchEngine;
+import org.eclipse.jdt.core.search.SearchPattern;
+import org.eclipse.jdt.core.search.TypeNameRequestor;
+import org.eclipse.jdt.internal.core.JavaModelManager;
+import org.eclipse.pde.core.plugin.IPluginModelBase;
+import org.eclipse.pde.core.plugin.PluginRegistry;
+import org.eclipse.pde.internal.core.SearchablePluginsManager;
+import org.eclipse.pde.internal.ui.wizards.imports.PluginImportOperation;
+import org.eclipse.pde.internal.ui.wizards.imports.PluginImportWizard;
+import org.eclipse.pde.ui.tests.runtime.TestUtils;
+import org.eclipse.pde.ui.tests.util.ProjectUtils;
+import org.eclipse.ui.IWorkbenchWindow;
+import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.handlers.IHandlerService;
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestName;
+import org.junit.rules.TestRule;
+
+/**
+ * Test that the External Plug-in Libraries project doesn't find duplicated
+ * types, when a project is imported into the workspace.
+ */
+public class ExternalJavaSearchClasspathContainerTests {
+
+	public static final String ADD_PLUGINS_TO_SEARCH_COMMAND_ID = "org.eclipse.pde.ui.addAllPluginsToJavaSearch";
+	@ClassRule
+	public static final TestRule CLEAR_WORKSPACE = ProjectUtils.DELETE_ALL_WORKSPACE_PROJECTS_BEFORE_AND_AFTER;
+	@Rule
+	public final TestRule deleteCreatedTestProjectsAfter = ProjectUtils.DELETE_CREATED_WORKSPACE_PROJECTS_AFTER;
+	@Rule
+	public final TestName name = new TestName();
+
+	@Test
+	public void testSearchWithImportedProject() throws Exception {
+		IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
+		IHandlerService handlerService = window.getService(IHandlerService.class);
+		handlerService.executeCommand(ADD_PLUGINS_TO_SEARCH_COMMAND_ID, null);
+		TestUtils.waitForJobs(name.getMethodName(), 100, 10000);
+		JavaModelManager.getIndexManager().waitForIndex(false, null);
+		IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
+		IProject proxyProject = root.getProject(SearchablePluginsManager.PROXY_PROJECT_NAME);
+		assertNotNull("Adding " + SearchablePluginsManager.PROXY_PROJECT_NAME + " failed", proxyProject);
+		IJavaProject javaProject = JavaCore.create(proxyProject);
+
+		String pluginId = "org.eclipse.core.expressions";
+		String fqn = "org.eclipse.core.expressions.AndExpression";
+		// expect a match like this:
+		// .../plugins/org.eclipse.equinox.common_3.20.300.v20251111-0312.jar|org/eclipse/core/runtime/IProgressMonitor.class
+		String expected = ".*.jar\\|" + fqn.replace('.', '/') + ".class";
+
+		List<String> matches = performSearch(javaProject, fqn);
+		assertSingleMatch(expected, matches);
+
+		IPluginModelBase plugin = PluginRegistry.findModel(pluginId);
+		IPluginModelBase[] plugins = { plugin };
+		// import as binary so we don't have to compile, compiling will likely fail
+		PluginImportWizard.doImportOperation(PluginImportOperation.IMPORT_BINARY, plugins, true, false, null, null);
+		TestUtils.waitForJobs(name.getMethodName(), 100, 10000);
+		JavaModelManager.getIndexManager().waitForIndex(false, null);
+		IProject pluginProject = root.getProject(pluginId);
+		assertNotNull("Importing " + pluginId + " failed", pluginProject);
+
+		// expect a match like this:
+		// /org.eclipse.core.expressions/org.eclipse.core.expressions_3.9.500.v20250608-0434.jar|org/eclipse/core/expressions/AndExpression.class
+		expected = pluginProject.getFullPath() + ".*.jar\\|" + fqn.replace('.', '/') + ".class";
+		matches = performSearch(javaProject, fqn);
+		assertSingleMatch(expected, matches);
+	}
+
+	private static void assertSingleMatch(String regexp, List<String> matches) {
+		assertEquals("Expected only one search match, but found: " + matches, 1, matches.size());
+		Pattern pattern = Pattern.compile(regexp);
+		Matcher matcher = pattern.matcher(matches.get(0));
+		assertTrue("Unexpected search matches: " + matches + ", should match regexp: " + regexp, matcher.matches());
+	}
+
+	private static List<String> performSearch(IJavaProject javaProject, String fqn) throws JavaModelException {
+		TestRequestor requestor = new TestRequestor();
+		SearchEngine searchEngine = new SearchEngine();
+		searchEngine.searchAllTypeNames(
+				fqn.substring(0, fqn.lastIndexOf('.')).toCharArray(),
+				SearchPattern.R_EXACT_MATCH | SearchPattern.R_CASE_SENSITIVE,
+				fqn.substring(fqn.lastIndexOf('.') + 1).toCharArray(),
+				SearchPattern.R_EXACT_MATCH | SearchPattern.R_CASE_SENSITIVE,
+				IJavaSearchConstants.TYPE,
+				SearchEngine.createJavaSearchScope(new IJavaElement[] { javaProject }),
+				requestor,
+				IJavaSearchConstants.WAIT_UNTIL_READY_TO_SEARCH,
+				new NullProgressMonitor());
+		List<String> matches = requestor.matches;
+		return matches;
+	}
+
+	private static class TestRequestor extends TypeNameRequestor {
+
+		private final List<String> matches = new ArrayList<>();
+
+		@Override
+		public void acceptType(int modifiers, char[] packageName, char[] simpleTypeName, char[][] enclosingTypeNames, String path) {
+			matches.add(path);
+		}
+	}
+}

ui/org.eclipse.pde.ui.tests/src/org/eclipse/pde/ui/tests/AllPDETests.java

@@ -16,6 +16,7 @@
 import org.eclipse.pde.core.tests.internal.AllPDECoreTests;
 import org.eclipse.pde.core.tests.internal.classpath.ClasspathResolutionTest;
 import org.eclipse.pde.core.tests.internal.classpath.ClasspathResolutionTest2;
+import org.eclipse.pde.core.tests.internal.classpath.ExternalJavaSearchClasspathContainerTests;
 import org.eclipse.pde.core.tests.internal.core.builders.BundleErrorReporterTest;
 import org.eclipse.pde.core.tests.internal.util.PDESchemaHelperTest;
 import org.eclipse.pde.ui.tests.build.properties.AllValidatorTests;
@@ -65,6 +66,7 @@
 	DynamicPluginProjectReferencesTest.class, //
 	ClasspathResolutionTest.class, //
 	ClasspathResolutionTest2.class, //
+		ExternalJavaSearchClasspathContainerTests.class, //
 	BundleErrorReporterTest.class, //
 	AllPDECoreTests.class, //
 	ProjectSmartImportTest.class, //