diff --git a/util/semver/constraint.go b/util/semver/constraint.go
index 8e2e27c..727afdf 100644
--- a/util/semver/constraint.go
+++ b/util/semver/constraint.go
@@ -74,7 +74,7 @@ func (sys System) ParseConstraint(str string) (retC *Constraint, retErr error) {
 	// creating the empty set, which means the opposite.
 	lexStr := str
 	if lexStr == "" {
-		if sys == NuGet {
+		if sys == NuGet || sys == Maven {
 			return nil, fmt.Errorf("invalid empty constraint")
 		}
 		lexStr = ">=0.0.0"
diff --git a/util/semver/maven_test.go b/util/semver/maven_test.go
index 05b9f38..eb7375e 100644
--- a/util/semver/maven_test.go
+++ b/util/semver/maven_test.go
@@ -81,6 +81,7 @@ func TestMavenCanon(t *testing.T) {
 }
 
 var mavenConstraintErrorTests = []constraintErrorTest{
+	{"", "invalid empty constraint"},
 	{"[", "expected comma or closing bracket in `[`"},
 	{"()", "hard requirement must be closed on both ends in `()`"},
 	{")", "unexpected rbracket in `)`"},