DivLoader.java

import java.util.concurrent.TimeUnit

class DivLoader {
    private final Object locker = new Object[0];
    private final AtomicBoolean running = new AtomicBoolean();
    private static final long WAIT_TIME = TimeUnit.SECONDS.toMillis(60);
    private Thread thread;
    private final AtomicReference<String> content = new AtomicReference<>();
    
    private Runnable refresher() {
        return () -> {
            running.set(true);
            synchronized (locker) {
                while (!Thread.interrupted()) {
                    try {
                        reloadDivContent();
                        Thread.sleep(WAIT_TIME);
                    } catch (InterruptedException e) {
                        break;
                    }
                }
                running.set(false);
                thread = null;
            }
        }
    }
    
    public boolean isRefreshing() {
        return running.get();
    }
    
    public void startRefresher() {
        if (isRefreshing()) return;
        synchronized (locker) {
            thread = new Thread(refresher(), "Web Div reloader");
            thread.start();
        }
    }
    
    public void stopRefresher() {
        synchronized (locker) {
            if (thread != null) thread.interrupt();
        }
    }
    
    
    private void reloadDivContent() throws IOException {
        // Use tools to fetch the content
        content.set("Content of div here");
    }
    
    public String getContent() {
        return content.get();
    }
    
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}