diff --git a/count/count_classes.go b/count/count_classes.go
index 125a672..a070692 100644
--- a/count/count_classes.go
+++ b/count/count_classes.go
@@ -54,7 +54,7 @@ func JarClasses(path string) (int, error) {
 			}
 		}
 
-		if !strings.HasSuffix(path, ".jar") {
+		if !strings.HasSuffix(path, ".jar") || info.IsDir() {
 			return nil
 		}
 
@@ -67,7 +67,11 @@ func JarClasses(path string) (int, error) {
 
 		z, err := zip.OpenReader(path)
 		if err != nil {
-			return fmt.Errorf("unable to open ZIP %s\n%w", path, err)
+			if !(errors.Is(err, zip.ErrFormat)) {
+				return fmt.Errorf("unable to open ZIP %s\n%w", path, err)
+			} else {
+				return nil
+			}
 		}
 		defer z.Close()
 
diff --git a/count/count_classes_test.go b/count/count_classes_test.go
index 961135a..bdf5afd 100644
--- a/count/count_classes_test.go
+++ b/count/count_classes_test.go
@@ -64,10 +64,15 @@ func testCountClasses(t *testing.T, context spec.G, it spec.S) {
 		Expect(count.Classes(path)).To(Equal(0))
 	})
 
-	it("fails for empty zip/jar files without none in the name", func() {
-		Expect(ioutil.WriteFile(filepath.Join(path, "test.jar"), []byte{}, 0644)).To(Succeed())
+	it("skips directories with .jar suffix", func() {
+		Expect(os.MkdirAll(filepath.Join(path, "bad-dir.jar"), 0755)).To(Succeed())
 
-		_, err := count.Classes(path)
-		Expect(err).To(MatchError(ContainSubstring("zip: not a valid zip file")))
+		Expect(count.Classes(path)).To(Equal(0))
+	})
+
+	it("skips bad jar files", func() {
+		Expect(ioutil.WriteFile(filepath.Join(path, "bad-jar.jar"), []byte{}, 0755)).To(Succeed())
+
+		Expect(count.Classes(path)).To(Equal(0))
 	})
 }