title: rest api returns empty bracket for GET request
body: <p>I implemented Rest api with Spring Boot. In my controller class, I have code to handle GET request which will return JSON if record found.</p>
  
  <pre><code>// SeqController.java
  @Autowired
  private SeqService seqService;
  @RequestMapping( 
          value = "/api/seqs/{analysis_id}", 
          method = RequestMethod.GET, 
          produces = MediaType.APPLICATION_JSON_VALUE)
  public ResponseEntity&lt;List&lt;SeqTb&gt;&gt; getSeqByAnalysisId(@PathVariable("analysis_id") String analysis_id) {
      List&lt;SeqTb&gt; seqs = seqService.findByAnalysisId(analysis_id);
      return new ResponseEntity(seqs, HttpStatus.OK);
  }
  </code></pre>
  
  <p>I also create a bean class <code>SeqServiceBean</code> that extends the interface <code>SeqService</code> which in turn calls methods from the following JPA repository for query.</p>
  
  <pre><code>//SeqRepository.java
  @Repository
  public interface SeqRepository extends JpaRepository&lt;SeqTb, Integer&gt; {
  
      @Override
      public List&lt;SeqTb&gt; findAll();
  
      public List&lt;SeqTb&gt; findByAnalysisId(String analysisId);
  }
  </code></pre>
  
  <p>Problem is when I typed the url (<a href="http://localhost:8080/api/seqs/fdebfd6e-d046-4192-8b97-ac9f65dc2009" rel="nofollow">http://localhost:8080/api/seqs/fdebfd6e-d046-4192-8b97-ac9f65dc2009</a>) in my browser, it returned nothing but a pair of empty brackets. I just looked in the database and that record is indeed there. What did I do wrong?</p>