try {
      collection.add(sampleElement);
      fail("add succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

    assertCollectionsAreEquivalent(copy, collection);

    try {
      collection.addAll(siblingCollection);
      fail("addAll succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

    try {
      collection.add(sampleElement);
      fail("add succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

    assertCollectionsAreEquivalent(copy, collection);

    try {
      collection.addAll(siblingCollection);
      fail("addAll succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

        // created it here.
      }
    }
  }

  /**
   * Creates any necessary but nonexistent parent directories of the specified path. Note that if
   * this operation fails, it may have succeeded in creating some (but not all) of the necessary
   * parent directories. The parent directory is created with the given {@code attrs}.
   *

        // created it here.
      }
    }
  }

  /**
   * Creates any necessary but nonexistent parent directories of the specified path. Note that if
   * this operation fails, it may have succeeded in creating some (but not all) of the necessary
   * parent directories. The parent directory is created with the given {@code attrs}.
   *