Exposing partially constructed instances

Reordering.java

public class Reordering {

  private static Constructed constructed;

  public static void main(String[] args) throws Exception {
    new Thread(Reordering::constructForever).start();

    Thread.sleep(100);
    checkInitializationUntilFails();
  }

  private static void constructForever() {
    while (true) {
      constructed = new Constructed();
    }
  }

  private static void checkInitializationUntilFails() {
    while (true) {
      if (!constructed.initialized) {
        throw new IllegalStateException();
      }
    }
  }

  private static class Constructed {

    private boolean initialized;

    public Constructed() {
      initialized = true;
    }

  }

}

This doesn't work. But if you do what professionals do, it does.

For future reference:

• get jcstress
  • hg clone http://hg.openjdk.java.net/code-tools/jcstress/ jcstress
  • cd jcstress/
  • mvn clean install -pl tests-custom -am
• execute UnsafePublication:
  • java -XX:-UseCompressedOops -jar tests-custom/target/jcstress.jar -t .*UnsafePublication.* -v

My results:

 (ETA:        n/a) (R: 0.00E+00) (T:   1/0) (F: 1/1) (I: 1/5)       [OK] o.o.j.t.unsafe.UnsafePublication
  Observed state   Occurrences   Expectation  Interpretation                                              
            [-1]   120,403,564    ACCEPTABLE  The object is not yet published                             
             [0]           549    ACCEPTABLE  The object is published, but all fields are 0.              
             [1]         1,766    ACCEPTABLE  The object is published, at least 1 field is visible.       
             [2]         1,908    ACCEPTABLE  The object is published, at least 2 fields are visible.     
             [3]         3,751    ACCEPTABLE  The object is published, at least 3 fields are visible.     
             [4]     4,185,752    ACCEPTABLE  The object is published, all fields are visible.