src/main/java/org/java_websocket/server/WebSocketServer.java
public void broadcast(String text, Collection<WebSocket> clients) {
		if (text == null || clients == null) {
			throw new IllegalArgumentException();
		}
		doBroadcast(text, clients);
	}
public void broadcast(String text, Collection<WebSocket> clients) {
		if (text == null || clients == null) {
			throw new IllegalArgumentException();
		}
		doBroadcast(text, clients);
	}
Send a text to a specific collection of websocket connections
@param text the text to send to the endpoints
@param clients a collection of endpoints to whom the text has to be send