### Question:
MeterIdConverter implements AttributeConverter<MeterId, Long> { @Override public MeterId toEntityAttribute(Long value) { if (value == null) { return null; } return new MeterId(value); }  @Override Long toGraphProperty(MeterId value); @Override MeterId toEntityAttribute(Long value); static final MeterIdConverter INSTANCE; }### Answer:
@Test public void shouldConvertStringToId() { MeterId meterId = new MeterId(0x123); MeterId actualEntity = MeterIdConverter.INSTANCE.toEntityAttribute(meterId.getValue()); assertEquals(meterId, actualEntity); }