Java Set in Object giving empty JSON array

Question

I recently upgraded my project from Spring boot 1.2.4 to 2.0.0. However, the response I receive from the controller given below, produces an empty json array for the portion that should be mapped to the Set webappLocales in the dto object. I put up some print statements, to check the contents, which are populated correctly. In fact, the inner ProjectDTO which also has some Set fields, which get converted correctly to json array. You can find the a snippet of the output and the respective code below.

DTO

public class WebappDTO {

    private long id;

    private String name;

    private Locale coreLocale;

    private Set<WebappLocale> webappLocales;

    private List<ProjectDTO> projects;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Locale getCoreLocale() {
        return coreLocale;
    }

    public void setCoreLocale(Locale coreLocale) {
        this.coreLocale = coreLocale;
    }

    public Set<WebappLocale> getWebappLocales() {
        return webappLocales;
    }

    public void setWebappLocales(Set<WebappLocale> webappLocales) {
        for (WebappLocale single: webappLocales) {
            System.out.println("-----INNER TEST TEST----" + single.getLocale().toString());
        }
        this.webappLocales = webappLocales;
    }

    public List<ProjectDTO> getProjects() {
        return projects;
    }

    public void setProjects(List<ProjectDTO> projectdto) {
        this.projects = projectdto;
    }

}

REST Controller

@ApiOperation(value = "Get webapps for current user")
@RequestMapping(value = "/getAll", method = RequestMethod.GET, produces = {
        "application/json" })
@PostFilter("hasPermission(filterObject.getId(), 'com.adobe.onyx.server.model.Webapp', 'read')")
public List<WebappDTO> fetchAll() {
    List<ProjectDTO> projectDTO;
    Set<ProjectConfig> projects;
    List<WebappDTO> webappDTO = new ArrayList<WebappDTO>();

    List<Webapp> webapps = getAllWebapps();

    for (Webapp w : webapps) {

        WebappDTO wdto = new WebappDTO();
        wdto.setId(w.getId());
        wdto.setName(w.getName());
        wdto.setCoreLocale(w.getCoreLocale());
        wdto.setWebappLocales(w.getWebappLocales());
        projects = w.getProjectConfig();
        projectDTO = new ArrayList<ProjectDTO>();

        for (ProjectConfig p : projects) {
            ProjectDTO pd = new ProjectDTO();
            pd.setId(p.getId());
            pd.setAlfProject(p.getAlfProject());
            pd.setMockBuildAvailable(p.isMockBuildAvailable());
            pd.setMockElementOrder(p.getMockElementOrder());
            pd.setMockPrefix(p.getMockPrefix());
            pd.setMockSuffix(p.getMockSuffix());
            pd.setName(p.getName());
            pd.setPlaceholderRegex(p.getPlaceholderRegex());
            pd.setPostProcessors(p.getPostProcessors());
            pd.setProjectStartDate(p.getProjectStartDate());
            pd.setJiraIssueTypeId(p.getJiraIssueTypeId());
            pd.setJiraPriorityId(p.getJiraPriorityId());
            pd.setJiraProjectId(p.getJiraProjectId());
            pd.setBugAssignee(p.getBugAssignee());
            projectDTO.add(pd);
        }
        wdto.setProjects(projectDTO);
        webappDTO.add(wdto);

        Set<WebappLocale> test = wdto.getWebappLocales();
        for (WebappLocale single: test) {
            System.out.println("-----OUTER TEST TEST----" + single.getLocale().toString());
        }

    }
    return webappDTO;
}

Web App Locale DTO

@Entity
@Table(name = "webapp_locales", uniqueConstraints = { 
@UniqueConstraint(columnNames = {
    "locale_id", "webapp_id" }) })
@XmlRootElement
public class WebappLocale implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
private long id;

@ManyToOne
@XmlTransient
@JsonIgnore
@JoinColumn(name = "locale_id")
private Locale locale;

@ManyToOne
@XmlTransient
@JsonIgnore
@JoinColumn(name = "webapp_id")
private Webapp webapp;

public long getId() {
    return id;
}

public void setId(long id) {
    this.id = id;
}

public Locale getLocale() {
    return locale;
}

public void setLocale(Locale locale) {
    this.locale = locale;
}

public Webapp getWebapp() {
    return webapp;
}

public void setWebapp(Webapp webapp) {
    this.webapp = webapp;
}
}

There are JsonIgnore on all fields. What do you expect should be the result? — Simon Martinelli, Apr 02 '20 at 09:38
I only ask myself, why would one to upgrade from an ancient unsupported version to an old unsupported version of a framework? https://github.com/spring-projects/spring-boot/wiki/Supported-Versions — mrkernelpanic, Apr 02 '20 at 10:22
So previously we were getting JSON objects containing only the id's — arjunkhera, Apr 02 '20 at 13:41
@mrkernelpanic I know. But we are running against a hard deadline, and this upgrade is required for db migration, changes are made for maintenance only — arjunkhera, Apr 02 '20 at 13:46

score 0 · Accepted Answer · answered Apr 13 '20 at 12:42

It appears that the upgrade does away with the Id field property in the REST response. I found some relevant answers here. Following is the solution that I followed in order to get around this problem. Find the original solution here

import java.util.stream.Collectors;

import javax.persistence.EntityManager;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.rest.core.config.RepositoryRestConfiguration;
import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurerAdapter;

@Configuration
public class MyRepositoryRestConfigurerAdapter extends RepositoryRestConfigurerAdapter {

    @Autowired
    private EntityManager entityManager;

    @Override
    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
        config.exposeIdsFor(entityManager.getMetamodel().getEntities().stream().map(e -> e.getJavaType()).collect(Collectors.toList()).toArray(new Class[0]));
    }

}

Java Set in Object giving empty JSON array

1 Answers1