### Question:
ColumnMappingUtils { public static ColumnMappings copy(ColumnMappings source) { ColumnMappings copy = new ColumnMappings(); copy.getColumnMapping() .addAll(source.getColumnMapping().stream().map(ColumnMappingUtils::copy).collect(Collectors.toList())); return copy; } private  ColumnMappingUtils(); static ColumnMappings copy(ColumnMappings source);  }### Answer:
@Test public void testCopy() { ColumnMappings orig = ColumnMappingUtilsTest.newColumnMappings(); ColumnMappings copy = ColumnMappingUtils.copy(orig); assertEquals(orig, copy); }