diff --git a/java/builder.go b/java/builder.go
index 4bdea28..ff5de09 100644
--- a/java/builder.go
+++ b/java/builder.go
@@ -375,8 +375,11 @@
 type classpath []android.Path
 
 func (x *classpath) FormJavaClassPath(optName string) string {
+	if optName != "" && !strings.HasSuffix(optName, "=") && !strings.HasSuffix(optName, " ") {
+		optName += " "
+	}
 	if len(*x) > 0 {
-		return optName + " " + strings.Join(x.Strings(), ":")
+		return optName + strings.Join(x.Strings(), ":")
 	} else {
 		return ""
 	}