diff --git a/ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/search/dependencies/GatherUnusedDependenciesOperation.java b/ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/search/dependencies/GatherUnusedDependenciesOperation.java
index 88836cd3a8b..e608c6be0f9 100644
--- a/ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/search/dependencies/GatherUnusedDependenciesOperation.java
+++ b/ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/search/dependencies/GatherUnusedDependenciesOperation.java
@@ -397,8 +397,8 @@ private void minimizeDependencies(Map<String, IPluginImport> usedPlugins, List<I
 
 	private static class Requestor extends SearchRequestor {
 		private volatile boolean used;
-		private SearchEngine engine;
-		private IJavaSearchScope searchScope;
+		private final SearchEngine engine;
+		private final IJavaSearchScope searchScope;
 
 		public Requestor(SearchEngine engine, IJavaSearchScope searchScope) {
 			this.engine = engine;