Read field stale value after object construction

Question

I\'m reading a book "Java concurrency in practice" by Brian Goetz. Paragraphs 3.5 and 3.5.1 contains statements that I can not understand.

Consider the followin

Answer 1

Did not reproduce it with your code. Here is an example to emulate un-safe publication. The strategy is let one thread publication Holder and let another check its value.

class Holder {
    private volatile int value;

    public Holder(int value, HolderContainer container) {
        container.holder = this;  // publication this object when it is not initilized properly
        try {
            Thread.sleep(10);  
        } catch (Exception e) {

        }
        this.value = value; // set value
    }

    public int getValue() {
        return value;
    }
}

class HolderContainer {

    public Holder holder;

    public Holder getHolder() { 
        if (holder == null) { 
            holder = new Holder(42, this);
        }
        return holder;
    }
}


public class Tests {

    public static void main(String[] args) {
        for (int loop = 0; loop < 1000; loop++) {
            HolderContainer holderContainer = new HolderContainer();
            new Thread(() -> holderContainer.getHolder()).start();
            new Thread(() -> {
                Holder holder = holderContainer.getHolder();
                int value1 = holder.getValue();  // might get default value
                try {
                    Thread.sleep(10);
                } catch (Exception e) {

                }
                int value2 = holder.getValue(); // might get custom value
                if (value1 != value2) {
                    System.out.println(value1 + "--->" + value2);
                }
            }).start();
        }
    }

}