diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java
index fbb24c157..b0f772e0a 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java
@@ -133,7 +133,9 @@ public class SubmoduleAddCommand extends
 	 */
 	protected boolean submoduleExists() throws IOException {
 		TreeFilter filter = PathFilter.create(path);
-		return SubmoduleWalk.forIndex(repo).setFilter(filter).next();
+		try (SubmoduleWalk w = SubmoduleWalk.forIndex(repo)) {
+			return w.setFilter(filter).next();
+		}
 	}
 
 	/**
@@ -178,7 +180,11 @@ public class SubmoduleAddCommand extends
 		clone.setURI(resolvedUri);
 		if (monitor != null)
 			clone.setProgressMonitor(monitor);
-		Repository subRepo = clone.call().getRepository();
+		Repository subRepo = null;
+		try (Git git = clone.call()) {
+			subRepo = git.getRepository();
+			subRepo.incrementOpen();
+		}
 
 		// Save submodule URL to parent repository's config
 		StoredConfig config = repo.getConfig();