With over 8 years of comprehensive experience in Android app development, I am confident that I can deliver exactly what you're looking for in your video/voice calling app project. My strong understanding of the Android SDK, APIs, and Java programming language will enable me to ensure optimal functionality while maintaining a seamlessly secure environment where user privacy is protected.
While I respect your preference against using Kotlin for this particular project, I've remained more than flexible with my toolkit, also specializing in Swift, Flutter, and IOS. My understanding of security principles is underscored by my experience in handling projects such as yours and integrating effective security measures without compromising on user-friendliness or performance speed.
It is essential to mention that as an Android/IoT specialist with a profound knowledge of IoT protocols like MQTT, TCP, WS, WSS, and TLS, I have facilitated the development of efficient real-time communication software. If given the opportunity to work on your project, the experience and expertise my team brings will provide the most time-efficient and optimized path to success. Let's get started!