Seems to be better if initializing mLoadDataForTest only when needed. 
public void loadDataForTest(String data, String mimeType, boolean isBase64Encoded) {
  if (mLoadDataForTest == null) {
    mLoadDataForTest = lookupMethod("loadDataForTest", String.class, String.class, boolean.class);
  }
   invokeMethod(mLoadDataForTest, mInstance, data, mimeType, isBase64Encoded);
}
```

The same pattern should be applied to `mGetTitleForTest` and `mSetCallbackForTest`.