diff --git a/android/src/main/java/com/reactnativecompressor/NitroPromiseAdapter.java b/android/src/main/java/com/reactnativecompressor/NitroPromiseAdapter.java
new file mode 100644
index 0000000..8d149f3
--- /dev/null
+++ b/android/src/main/java/com/reactnativecompressor/NitroPromiseAdapter.java
@@ -0,0 +1,105 @@
+package com.reactnativecompressor;
+
+import com.facebook.react.bridge.Promise;
+import com.facebook.react.bridge.WritableMap;
+import java.util.concurrent.atomic.AtomicBoolean;
+import kotlin.Unit;
+import kotlin.jvm.functions.Function0;
+import kotlin.jvm.functions.Function1;
+
+/**
+ * Adapts the React Native bridge {@link Promise} to a Nitro
+ * {@link com.margelo.nitro.core.Promise} so the existing domain methods — which speak the bridge
+ * {@code Promise} contract ({@code resolve}/{@code reject}) — can drive a Nitro Promise unchanged.
+ *
+ * <p>{@code convert} maps the resolved bridge value to the Nitro result type {@code T};
+ * {@code onSettle} runs once on resolve/reject (used to unregister progress callbacks).
+ *
+ * <p>This is intentionally written in Java rather than Kotlin: the bridge {@code Promise} interface
+ * declares {@code code} as non-null ({@code String}) on some React Native versions and nullable
+ * ({@code String?}) on others. Kotlin override parameter types are invariant, so a single Kotlin
+ * source can only match one of those. Java erases nullability for override matching, so one Java
+ * implementation satisfies every React Native version.
+ */
+public class NitroPromiseAdapter<T> implements Promise {
+  private final com.margelo.nitro.core.Promise<T> promise;
+  private final Function1<Object, T> convert;
+  private final Function0<Unit> onSettle;
+  private final AtomicBoolean settled = new AtomicBoolean(false);
+
+  public NitroPromiseAdapter(
+      com.margelo.nitro.core.Promise<T> promise,
+      Function1<Object, T> convert,
+      Function0<Unit> onSettle) {
+    this.promise = promise;
+    this.convert = convert;
+    this.onSettle = onSettle;
+  }
+
+  @Override
+  public void resolve(Object value) {
+    if (!settled.compareAndSet(false, true)) return;
+    onSettle.invoke();
+    promise.resolve(convert.invoke(value));
+  }
+
+  private void rejectInternal(String message, Throwable throwable) {
+    if (!settled.compareAndSet(false, true)) return;
+    onSettle.invoke();
+    promise.reject(
+        throwable != null
+            ? throwable
+            : new Throwable(message != null ? message : "react-native-compressor error"));
+  }
+
+  @Override
+  public void reject(String code, String message) {
+    rejectInternal(message != null ? message : code, null);
+  }
+
+  @Override
+  public void reject(String code, Throwable throwable) {
+    rejectInternal(code, throwable);
+  }
+
+  @Override
+  public void reject(String code, String message, Throwable throwable) {
+    rejectInternal(message != null ? message : code, throwable);
+  }
+
+  @Override
+  public void reject(Throwable throwable) {
+    rejectInternal(throwable.getMessage(), throwable);
+  }
+
+  @Override
+  public void reject(Throwable throwable, WritableMap userInfo) {
+    rejectInternal(throwable.getMessage(), throwable);
+  }
+
+  @Override
+  public void reject(String code, WritableMap userInfo) {
+    rejectInternal(code, null);
+  }
+
+  @Override
+  public void reject(String code, Throwable throwable, WritableMap userInfo) {
+    rejectInternal(code, throwable);
+  }
+
+  @Override
+  public void reject(String code, String message, WritableMap userInfo) {
+    rejectInternal(message != null ? message : code, null);
+  }
+
+  @Override
+  public void reject(String code, String message, Throwable throwable, WritableMap userInfo) {
+    rejectInternal(message != null ? message : code, throwable);
+  }
+
+  @Deprecated
+  @Override
+  public void reject(String message) {
+    rejectInternal(message, null);
+  }
+}
diff --git a/android/src/main/java/com/reactnativecompressor/NitroPromiseAdapter.kt b/android/src/main/java/com/reactnativecompressor/NitroPromiseAdapter.kt
deleted file mode 100644
index a6c142a..0000000
--- a/android/src/main/java/com/reactnativecompressor/NitroPromiseAdapter.kt
+++ /dev/null
@@ -1,55 +0,0 @@
-package com.reactnativecompressor
-
-import com.facebook.react.bridge.Promise
-import com.facebook.react.bridge.WritableMap
-import java.util.concurrent.atomic.AtomicBoolean
-import com.margelo.nitro.core.Promise as NitroPromise
-
-/**
- * Adapts the React Native bridge [Promise] to a Nitro [NitroPromise] so the existing
- * domain methods — which speak the bridge `Promise` contract (`resolve`/`reject`) — can
- * drive a Nitro Promise unchanged.
- *
- * [convert] maps the resolved bridge value to the Nitro result type [T];
- * [onSettle] runs once on resolve/reject (used to unregister progress callbacks).
- */
-class NitroPromiseAdapter<T>(
-  private val promise: NitroPromise<T>,
-  private val convert: (Any?) -> T,
-  private val onSettle: () -> Unit = {},
-) : Promise {
-  private val settled = AtomicBoolean(false)
-
-  override fun resolve(value: Any?) {
-    if (!settled.compareAndSet(false, true)) return
-    onSettle()
-    promise.resolve(convert(value))
-  }
-
-  private fun rejectInternal(message: String?, throwable: Throwable?) {
-    if (!settled.compareAndSet(false, true)) return
-    onSettle()
-    promise.reject(throwable ?: Throwable(message ?: "react-native-compressor error"))
-  }
-
-  override fun reject(code: String?, message: String?) = rejectInternal(message ?: code, null)
-
-  override fun reject(code: String?, throwable: Throwable?) = rejectInternal(code, throwable)
-
-  override fun reject(code: String?, message: String?, throwable: Throwable?) = rejectInternal(message ?: code, throwable)
-
-  override fun reject(throwable: Throwable) = rejectInternal(throwable.message, throwable)
-
-  override fun reject(throwable: Throwable, userInfo: WritableMap) = rejectInternal(throwable.message, throwable)
-
-  override fun reject(code: String?, userInfo: WritableMap) = rejectInternal(code, null)
-
-  override fun reject(code: String?, throwable: Throwable?, userInfo: WritableMap) = rejectInternal(code, throwable)
-
-  override fun reject(code: String?, message: String?, userInfo: WritableMap) = rejectInternal(message ?: code, null)
-
-  override fun reject(code: String?, message: String?, throwable: Throwable?, userInfo: WritableMap?) = rejectInternal(message ?: code, throwable)
-
-  @Deprecated("Prefer passing a module-specific error code to JS.", ReplaceWith("reject(code, message)"))
-  override fun reject(message: String) = rejectInternal(message, null)
-}