title: Getting NumberFormatException using Spring Data JPA
body: <p>I'm learning Spring with "Spring in action 5" and faced some problem: when i switch to Spring Data JPA from JDBC (which is 100% working correctly) in chapter 3, the code stops working as i try to open main page with taco's ingredients. I made a few logs to see what's going on and found out that method findById(String id) can't convert my value from DB (or something like that). I'm using MySQL.</p>
  
  <p>I tried to call convertor's method convert(String id) by myself using @Autowired, but the only thing i discovered was that when key is wrong, another error will appear. So data is visible. I will try to provide some code here, but i'm not sure what is useful and what is not. I'm getting error on the first attemp to log something. Errors in IDE and in browser are different.
  Here's full project <a href="https://github.com/thedistantblue/taco-cloud-jpa" rel="nofollow noreferrer">https://github.com/thedistantblue/taco-cloud-jpa</a>.</p>
  
  <p>Here's my converter:</p>
  
  <pre><code>    public class IngredientByIdConverter implements Converter&lt;String, 
      Ingredient&gt; {
  
      private IngredientRepository ingredientRepo;
  
      @Autowired
      public IngredientByIdConverter(IngredientRepository ingredientRepo) {
          this.ingredientRepo = ingredientRepo;
  
      }
      @Override
          public Ingredient convert(String id) {
              log.info("In converter.convert(): " 
          +ingredientRepo.findById(id).toString());
              Optional&lt;Ingredient&gt; optionalIngredient = 
          ingredientRepo.findById(id);
              return optionalIngredient.orElse(null);
          }
      }
  </code></pre>
  
  <p>And controller class:</p>
  
  <pre><code>    @Slf4j
      @Controller
      @RequestMapping("/design")
      @SessionAttributes("order")
      public class DesignTacoController {
  
      @ModelAttribute(name = "order")
      public Order order() {
          return new Order();
      }
  
      @ModelAttribute(name = "taco")
      public Taco taco() {
          return new Taco();
      }
  
      private final IngredientRepository ingredientRepository;
      private TacoRepository designRepository;
      private IngredientByIdConverter converter;
  
      @Autowired
      public DesignTacoController(IngredientRepository ingredientRepository,
                                  TacoRepository designRepository,
                                  IngredientByIdConverter converter) {
          this.ingredientRepository = ingredientRepository;
          this.designRepository = designRepository;
          this.converter = converter;
      }
  
      @GetMapping
      public String showDesignForm(Model model) {
          List&lt;Ingredient&gt; ingredients = new ArrayList&lt;&gt;();
  
  
  
          log.info(converter.convert("CARN").getName());
          log.info("in DTC: " + ingredientRepository.findAll());
  
          ingredientRepository.findAll().forEach(i -&gt; ingredients.add(i));
  </code></pre>
  
  <p>In IDE:</p>
  
  <p>java.lang.NumberFormatException: For input string: "PROTEIN"
   at  java.base/jdk.internal.math.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2054) ~[na:na]
      at java.base/jdk.internal.math.FloatingDecimal.parseDouble(FloatingDecimal.java:110) ~[na:na]
      at java.base/java.lang.Double.parseDouble(Double.java:543) ~[na:na]</p>
  
  <p>In browser:</p>
  
  <p>There was an unexpected error (type=Internal Server Error, status=500).
  For input string: "PROTEIN"; nested exception is java.lang.NumberFormatException: For input string: "PROTEIN"
  org.springframework.dao.InvalidDataAccessApiUsageException: For input string: "PROTEIN"; nested exception is java.lang.NumberFormatException: For input string: "PROTEIN"
      at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:373)
      at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:255)
      at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:527)
      at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61)
      at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242)
      at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153)
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)</p>