diff --git a/pkg/flink/resources.go b/pkg/flink/resources.go
index f708bd7..7c97d28 100644
--- a/pkg/flink/resources.go
+++ b/pkg/flink/resources.go
@@ -70,6 +70,15 @@ func (gcsDownloader) Container(artifacts []string) corev1.Container {
 
 type DownloaderRegistry map[string]Downloader
 
+func (dr DownloaderRegistry) GetDownloader(scheme string) (Downloader, error) {
+	d, ok := dr[scheme]
+	if !ok {
+		return nil, fmt.Errorf("downloader not implemented for scheme: %s", scheme)
+	}
+
+	return d, nil
+}
+
 var downloaderRegistry = DownloaderRegistry{
 	"":   localDownloader{},
 	"gs": gcsDownloader{},
@@ -219,12 +228,15 @@ func (fc *FlinkCluster) updateJobSpec(taskCtx FlinkTaskContext) error {
 	volumeName := fmt.Sprintf("%s-jars", taskCtx.ClusterName.String())
 	out.Volumes = append(out.Volumes, corev1.Volume{Name: volumeName})
 	out.VolumeMounts = append(out.VolumeMounts, corev1.VolumeMount{Name: volumeName, MountPath: jarsVolumePath})
+	out.JarFile = defaultJarFile
 
 	for scheme, urls := range groupBy {
-		out.JarFile = defaultJarFile
-		out.InitContainers = append(out.InitContainers, downloaderRegistry[scheme].Container(urls))
+		downloader, err := downloaderRegistry.GetDownloader(scheme)
+		if err != nil {
+			return err
+		}
+		out.InitContainers = append(out.InitContainers, downloader.Container(urls))
 	}
-
 	out.InitContainers = append(out.InitContainers, artifactZip)
 
 	return nil
@@ -263,7 +275,9 @@ func NewFlinkCluster(config *Config, taskCtx FlinkTaskContext) (*flinkOp.FlinkCl
 
 	cluster.updateJobManagerSpec(taskCtx)
 	cluster.updateTaskManagerSpec(taskCtx)
-	cluster.updateJobSpec(taskCtx)
+	if err := cluster.updateJobSpec(taskCtx); err != nil {
+		return nil, err
+	}
 
 	// fill in defaults
 	resource := flinkOp.FlinkCluster(cluster)
diff --git a/pkg/flink/resources_test.go b/pkg/flink/resources_test.go
index a75298d..82523c7 100644
--- a/pkg/flink/resources_test.go
+++ b/pkg/flink/resources_test.go
@@ -281,3 +281,21 @@ func TestBuildFlinkClusterSpecJobCommand(t *testing.T) {
 	}
 	assert.Assert(t, reflect.DeepEqual(initCont.Args, args))
 }
+
+func TestBuildFlinkClusterWithUnsupportedSchemeJar(t *testing.T) {
+	job := flinkIdl.FlinkJob{
+		JarFiles: []string{"http://bucket.com/artifact0.jar"},
+	}
+	config := GetFlinkConfig()
+
+	flinkCtx := FlinkTaskContext{
+		ClusterName: ClusterName("generated-name"),
+		Namespace:   "test-namespace",
+		Annotations: make(map[string]string),
+		Labels:      make(map[string]string),
+		Job:         job,
+	}
+
+	_, err := NewFlinkCluster(config, flinkCtx)
+	assert.Error(t, err, "downloader not implemented for scheme: http")
+}