diff --git a/library/modules/platform/android.sx b/library/modules/platform/android.sx
index 180dd4d..98885ba 100644
--- a/library/modules/platform/android.sx
+++ b/library/modules/platform/android.sx
@@ -134,31 +134,56 @@ sx_android_activity_clazz :: (activity: *void) -> *void {
     sx_load_ptr_at(activity, ANATIVEACTIVITY_CLAZZ_OFFSET);
 }
 
-// sx-side reimplementation of the JNI dispatch chain inside
-// `sx_android_query_safe_insets`. Caller provides an already-attached
-// `JNIEnv*` and the activity's `clazz` jobject. Outputs physical-pixel
-// insets just like the C foreign helper above. Eventually replaces
-// the foreign call once the JavaVM env-attach plumbing has a sx
-// equivalent or a thinner C shim.
-sx_query_safe_insets_jni :: (env: *void, activity: *void, top: *s32, left: *s32, bottom: *s32, right: *s32) -> void {
+// Declarative JNI class bindings for the safe-insets dispatch chain
+// (Phase 2D migration). Each `#jni_class` declares the sx-side alias,
+// the JNI class path, and the methods we use — `inst.method(args)`
+// inside a `#jni_env(env) { ... }` scope lowers to the same JNI vtable
+// indirection as the hand-rolled `#jni_call` form, with the descriptor
+// auto-derived from the sx signature (see [src/ir/jni_descriptor.zig]).
+WindowInsets :: #jni_class("android/view/WindowInsets") {
+    getSystemWindowInsetTop    :: (self: *Self) -> s32;
+    getSystemWindowInsetLeft   :: (self: *Self) -> s32;
+    getSystemWindowInsetBottom :: (self: *Self) -> s32;
+    getSystemWindowInsetRight  :: (self: *Self) -> s32;
+}
+
+View :: #jni_class("android/view/View") {
+    getRootWindowInsets :: (self: *Self) -> *WindowInsets;
+}
+
+Window :: #jni_class("android/view/Window") {
+    getDecorView :: (self: *Self) -> *View;
+}
+
+Activity :: #jni_class("android/app/Activity") {
+    getWindow :: (self: *Self) -> *Window;
+}
+
+// sx-side reimplementation of the JNI dispatch chain. Caller provides
+// an already-attached `JNIEnv*` and the activity's `clazz` jobject
+// (cast to `*Activity` so the method-call DSL can find it in the
+// foreign-class registry). Outputs physical-pixel insets.
+sx_query_safe_insets_jni :: (env: *void, activity: *Activity, top: *s32, left: *s32, bottom: *s32, right: *s32) -> void {
     inline if OS != .android { return; }
 
     top.* = 0; left.* = 0; bottom.* = 0; right.* = 0;
     if activity == null { return; }
 
-    window := #jni_call(*void)(env, activity, "getWindow", "()Landroid/view/Window;");
-    if window == null { return; }
+    #jni_env(env) {
+        window := activity.getWindow();
+        if window == null { return; }
 
-    decor := #jni_call(*void)(env, window, "getDecorView", "()Landroid/view/View;");
-    if decor == null { return; }
+        decor := window.getDecorView();
+        if decor == null { return; }
 
-    insets := #jni_call(*void)(env, decor, "getRootWindowInsets", "()Landroid/view/WindowInsets;");
-    if insets == null { return; }
+        insets := decor.getRootWindowInsets();
+        if insets == null { return; }
 
-    top.*    = #jni_call(s32)(env, insets, "getSystemWindowInsetTop",    "()I");
-    left.*   = #jni_call(s32)(env, insets, "getSystemWindowInsetLeft",   "()I");
-    bottom.* = #jni_call(s32)(env, insets, "getSystemWindowInsetBottom", "()I");
-    right.*  = #jni_call(s32)(env, insets, "getSystemWindowInsetRight",  "()I");
+        top.*    = insets.getSystemWindowInsetTop();
+        left.*   = insets.getSystemWindowInsetLeft();
+        bottom.* = insets.getSystemWindowInsetBottom();
+        right.*  = insets.getSystemWindowInsetRight();
+    }
 }
 
 // EGL — display/surface/context/config are opaque to us.
@@ -396,7 +421,7 @@ impl Platform for AndroidPlatform {
                 attached : bool = false;
                 env := sx_android_get_env(g_android_activity, @attached);
                 if env != null {
-                    clazz := sx_android_activity_clazz(g_android_activity);
+                    clazz : *Activity = xx sx_android_activity_clazz(g_android_activity);
                     sx_query_safe_insets_jni(env, clazz, @t, @l, @b, @r);
                     if attached { sx_android_detach_env(g_android_activity); }
                 }