Before starting this topic lets a glimpse over some basic information about React Native and Flutter.
React Native is an open-source mobile application framework created by Facebook, Inc and released in 2015.
Flutter is an Google’s open-source UI toolkit.
It is used for building fast, beautiful, natively compiled applications for Android, iOS, Linux, Mac, Windows, Google Fuchsia, and the web with one programing language and single codebase. It used dart language which is completely object oriented language. For you’re from Java background it would be easier to go with Flutter.
Comparison between React Native and Flutter.
Conclusion : We cannot say which is better whether React Native or Flutter. As there is a huge community which is working on React Native and a huge community is also growing in terms of Flutter.
So its up to you that with which technology you want to go whether React Native or Flutter.