### Question:
StringArrayToStringConverter implements Converter<String[], String> { @Override public String convert(String[] source) { return ObjectUtils.isEmpty(source) ? null : StringUtils.arrayToCommaDelimitedString(source); }  @Override String convert(String[] source);  }### Answer:
@Test public void testConvert() { StringArrayToStringConverter converter = new StringArrayToStringConverter(); String value = converter.convert(new String[]{"Hello", "World"}); Assertions.assertEquals("Hello,World", value); value = converter.convert(new String[]{}); Assertions.assertNull(value); value = converter.convert(null); Assertions.assertNull(value); }