microg/GmsCore · error · IllegalArgumentException

Binder object is null.

Error message

Binder object is null.

What it means

During ObjectWrapper.unwrap, field.get(binder) threw a NullPointerException, which the library rethrows as IllegalArgumentException('Binder object is null.'). This means the field holding the wrapped object is null on that binder instance — effectively the wrapper wraps nothing (null) and the code path assumes non-null.

Source

Thrown at play-services-basement/src/main/java/com/google/android/gms/dynamic/ObjectWrapper.java:76

            }

            if (field == null) {
                field = currentField;
            } else {
                throw new IllegalArgumentException("Too many non-synthetic fields were found");
            }
        }

        if (field == null) {
            throw new IllegalArgumentException("No non-synthetic fields were found");
        }

        if (!field.isAccessible()) {
            field.setAccessible(true);
            try {
                return field.get(binder);
            } catch (NullPointerException localNullPointerException) {
                throw new IllegalArgumentException("Binder object is null.",
                        localNullPointerException);
            } catch (IllegalArgumentException localIllegalArgumentException) {
                throw new IllegalArgumentException("remoteBinder is the wrong class.",
                        localIllegalArgumentException);
            } catch (IllegalAccessException localIllegalAccessException) {
                throw new IllegalArgumentException("Could not access the field in remoteBinder.",
                        localIllegalAccessException);
            }
        } else {
            throw new IllegalArgumentException();
        }
    }

    @Nullable
    public static <T> T unwrapTyped(IObjectWrapper obj, Class<T> clazz) {
        try {
            return clazz.cast(unwrap(obj));
        } catch (ClassCastException e) {

View on GitHub (pinned to 157c9d86ac)

Solutions

1. Ensure the object passed to ObjectWrapper.wrap is non-null, or skip the call when you know it's null
2. Null-check the field value before wrapping: if (obj == null) return;
3. Catch IllegalArgumentException from unwrap* and treat it as 'value absent'
4. Return an Optional/nullable result instead of wrapping null

Example fix

// before
return ObjectWrapper.unwrapTyped(w, MyType.class); // NPE if w wraps null
// after
if (w == null) return null;
try {
    return ObjectWrapper.unwrapTyped(w, MyType.class);
} catch (IllegalArgumentException e) {
    return null;
}

if (wrapper == null) return null;
IBinder b = wrapper.asBinder();
for (Field f : b.getClass().getDeclaredFields()) {
    if (!f.isSynthetic()) { f.setAccessible(true); if (f.get(b) == null) return null; }
}

boolean isNonNullWrapper(IObjectWrapper w) {
    if (w == null) return false;
    try { ObjectWrapper.unwrap(w); return true; }
    catch (IllegalArgumentException e) { return false; }
}

try {
    T value = ObjectWrapper.unwrapTyped(wrapper, T.class);
} catch (IllegalArgumentException e) {
    value = null; // wrapped object was null
}

When it happens

Trigger: ObjectWrapper.wrap(null) or an ObjectWrapper constructed with a null field value, then passed across the binder interface and later unwrapped with unwrap()/unwrapTyped().

Common situations: Upstream API returning null wrapped in an ObjectWrapper; a field that failed to initialize before being wrapped; Optional-style flows where 'absent' is encoded as a null wrapper.

Related errors

• No fields were found
• Too many non-synthetic fields were found
• remoteBinder is the wrong class.
• suggested UID [
• suggested PID [

AI-assisted analysis of microg/GmsCore@157c9d86ac (2026-09-06). Data as JSON: /api/errors/9b3831d3444fa232. Report an issue: GitHub.