A unit test demonstrating the difference in JOL's layout and stats graph walkers (fails on v0.16)

WalkersDifferenceTest.java

package org.openjdk.jol.info;

import org.junit.Assert;
import org.junit.Test;


public class WalkersDifferenceTest {

  static class A {

  }

  static class B {
    private final A[] bs;

    B() {
      bs = new A[] { new A() };
    }
  }

  @Test
  public void layoutAndStatsDifference() {
    B b = new B();

    GraphLayout layout = GraphLayout.parseInstance(b);
    GraphStats stats = GraphStats.parseInstance(b);

    Assert.assertEquals(layout.totalSize(), stats.totalSize());
    Assert.assertEquals(layout.totalCount(), stats.totalCount());
  }
}