diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
index 47c747e80..c1535fa1f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
@@ -866,7 +866,10 @@ public abstract class FS {
 	 * @since 4.0
 	 */
 	public File findHook(Repository repository, final String hookName) {
-		final File hookFile = new File(new File(repository.getDirectory(),
+		File gitDir = repository.getDirectory();
+		if (gitDir == null)
+			return null;
+		final File hookFile = new File(new File(gitDir,
 				Constants.HOOKS), hookName);
 		return hookFile.isFile() ? hookFile : null;
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java
index b07f8594d..80c729007 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java
@@ -335,6 +335,9 @@ public class FS_POSIX extends FS {
 	@Override
 	public File findHook(Repository repository, String hookName) {
 		final File gitdir = repository.getDirectory();
+		if (gitdir == null) {
+			return null;
+		}
 		final Path hookPath = gitdir.toPath().resolve(Constants.HOOKS)
 				.resolve(hookName);
 		if (Files.isExecutable(hookPath))