diff --git a/java/androidmk.go b/java/androidmk.go
index 1c0526a..1a4b27d 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -36,7 +36,7 @@
 				}
 				if library.dexJarFile != nil {
 					fmt.Fprintln(w, "LOCAL_SOONG_DEX_JAR :=", library.dexJarFile.String())
-					if library.deviceProperties.Dex_preopt == nil || *library.deviceProperties.Dex_preopt == false {
+					if library.deviceProperties.Dex_preopt != nil && *library.deviceProperties.Dex_preopt == false {
 						fmt.Fprintln(w, "LOCAL_DEX_PREOPT := false")
 					}
 				}