DoubleCheckSingleton.java

public class SecuredCommunicationChannel {
    
    private static volatile SecuredCommunicationChannel instance;
    
    public static SecuredCommunicationChannel getInstance() {
        if (instance == null) {
            synchronized (SecuredCommunicationChannel.class) {
                if (instance == null) {
                    instance = new SecuredCommunicationChannel();
                }
            }
        }
        return instance;
    }
}