### Question:
TextColumn extends AbstractStringColumn<TextColumn> { @Override public TextColumn appendObj(Object obj) { if (obj == null) { return appendMissing(); } if (!(obj instanceof String)) { throw new IllegalArgumentException( "Cannot append " + obj.getClass().getName() + " to TextColumn"); } return append((String) obj); } private  TextColumn(String name, Collection<String> strings); private  TextColumn(String name); private  TextColumn(String name, String[] strings); static boolean valueIsMissing(String string); @Override TextColumn appendMissing(); static TextColumn create(String name); static TextColumn create(String name, String... strings); static TextColumn create(String name, Collection<String> strings); static TextColumn create(String name, int size); static TextColumn create(String name, Stream<String> stream); @Override boolean isMissing(int rowNumber); @Override TextColumn emptyCopy(); @Override TextColumn emptyCopy(int rowSize); @Override void sortAscending(); @Override void sortDescending(); @Override int size(); String get(int rowIndex); @Override List<String> asList(); @Override Table summary(); @Override void clear(); @Override TextColumn lead(int n); @Override TextColumn lag(int n); @Override TextColumn set(Selection rowSelection, String newValue); @Override TextColumn set(int rowIndex, String stringValue); @Override int countUnique(); @Override boolean contains(String aString); @Override TextColumn setMissing(int i); TextColumn addAll(List<String> stringValues); @Override TextColumn appendCell(String object); @Override TextColumn appendCell(String object, AbstractColumnParser<?> parser); @Override IntComparator rowComparator(); @Override boolean isEmpty(); @Override TextColumn unique(); TextColumn where(Selection selection); @Override TextColumn copy(); @Override TextColumn append(Column<String> column); @Override int countMissing(); @Override TextColumn removeMissing(); @Override Iterator<String> iterator(); Set<String> asSet(); @Override byte[] asBytes(int rowNumber); TextColumn append(String value); @Override TextColumn appendObj(Object obj); @Override Selection isIn(String... strings); @Override Selection isIn(Collection<String> strings); @Override Selection isNotIn(String... strings); @Override Selection isNotIn(Collection<String> strings); int firstIndexOf(String value); @Override String[] asObjectArray(); @Override StringColumn asStringColumn();  }### Answer:
@Test public void testAppendObj() { TextColumn column = TextColumn.create("testing"); column.appendObj("Value 1"); column.appendObj(null); column.appendObj("Value 2"); assertEquals(3, column.size()); }