* the {@code x} and {@code y} values must both have non-zero population variance (i.e. {@code
   * xStats().populationVariance() > 0.0 && yStats().populationVariance() > 0.0}). The result is not
   * guaranteed to be exactly +/-1 even when the data are perfectly (anti-)correlated, due to
   * numerical errors. However, it is guaranteed to be in the inclusive range [-1, +1].
   *
   * <h3>Non-finite values</h3>
   *

    public boolean equals(@Nullable Object o) {
      return o == this || o == null;
    }

    @Override
    public int hashCode() {
      return 0;
    }
  }

  /** Test class that returns true even if the test object is of the wrong class */
  private static class InvalidEqualsIncompatibleClassObject {

    @Override
    public boolean equals(@Nullable Object o) {
      return o != null;
    }

    return new JavaIoCreator();
  }

  /**
   * Creates the permissions normally used for Windows filesystems, looking up the user afresh, even
   * if previous calls have initialized the {@code PermissionSupplier} fields.
   *
   * <p>This lets us test the effects of different values of the {@code user.name} system property

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// This program is distributed in the hope that it will be useful
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// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License

// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License

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