I want to receive in turn two strings sent from server via websocket in Java [closed]

I want to receive in turn two strings sent from server via websocket in JavaScript. Then concatenate those two strings. How should I write the code?

zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz