diff --git a/java/BUCK b/java/BUCK
index 937267f6f6..14210ed140 100644
--- a/java/BUCK
+++ b/java/BUCK
@@ -20,6 +20,9 @@ yoga_cxx_library(
         "-std=c++11",
     ],
     platforms = ANDROID,
+    preprocessor_flags = [
+        "-DFBJNI_WITH_FAST_CALLS",
+    ],
     soname = "libyoga.$(ext)",
     visibility = ["PUBLIC"],
     deps = [
diff --git a/java/com/facebook/yoga/YogaJNI.java b/java/com/facebook/yoga/YogaJNI.java
index 6e036c4a70..deccbcf5d5 100644
--- a/java/com/facebook/yoga/YogaJNI.java
+++ b/java/com/facebook/yoga/YogaJNI.java
@@ -10,6 +10,10 @@
 import com.facebook.soloader.SoLoader;
 
 public class YogaJNI {
+
+  // Known constants. 1-3 used in previous experiments. Do not reuse.
+  public static int JNI_FAST_CALLS = 4;
+
   // set before loading any other Yoga code
   public static boolean useFastCall = false;