我有同样的问题，但它是当集合为空。只有在Set集合中，在List中工作正常。您可以尝试使用hibernate注释@LazyCollection(LazyCollectionOption.FALSE)而不是JPA注释fetch = FetchType.EAGER。

我的解决方案: 这是我的配置和工作良好

@OneToMany(mappedBy = "format", cascade = CascadeType.ALL, orphanRemoval = true)
@LazyCollection(LazyCollectionOption.FALSE)
private Set<Barcode> barcodes;

@OneToMany(mappedBy = "format", cascade = CascadeType.ALL, orphanRemoval = true)
@LazyCollection(LazyCollectionOption.FALSE)
private List<FormatAdditional> additionals;

从[Intellij Idea] 2020.3版本批量运行测试时，spring-boot 2.4.1出现此问题。从IntelliJ一次只运行一个测试或从命令行运行测试时，不会出现此问题。

也许是Intellij缓存问题?

跟进:

The problem appears when running tests using the maven-surefire-plugin reuseForks true. Using reuseForks false would provide a quick fix, but the tests running time will increase dramatically. Because we are reusing forks, the database context might become dirty due to other tests that are run - without cleaning the database context afterwards. The obvious solution would be to clean the database context before running a test, but the best one should be to clean up the database context after each test (solving the root cause of the original problem). Using the @Transactional annotation on your test methods will guarantee that your database changes are rolled back at the end of the test methods. See the Spring documentation on transactions: https://docs.spring.io/spring-framework/docs/current/reference/html/testing.html#testcontext-tx.

方法:

public void setChildren(Set<SonEntity> aSet) {
    this.sonEntities = aSet;
}

如果分离了parentEntity，工作，如果我们更新它。 但是如果实体没有从每个上下文中分离出来(即查找和更新操作在同一个事务中)，下面的方法是有效的。

public void setChildren(Set<SonEntity> aSet) {
    //this.sonEntities = aSet; //This will override the set that Hibernate is tracking.
    this.sonEntities.clear();
    if (aSet != null) {
        this.sonEntities.addAll(aSet);
    }
}

我唯一一次得到这个错误是当我试图将NULL传递到集合的setter时。为了防止这种情况，我的setter是这样的:

public void setSubmittedForms(Set<SubmittedFormEntity> submittedForms) {
    if(submittedForms == null) {
        this.submittedForms.clear();
    }
    else {
        this.submittedForms = submittedForms;
    }
}

我使用Spring Boot，有这个问题与一个集合，尽管没有直接覆盖它，因为我声明了一个额外的字段为同一个集合与自定义序列化和反序列化，以提供一个更前端友好的数据表示:

  public List<Attribute> getAttributes() {
    return attributes;
  }

  public void setAttributes(List<Attribute> attributes) {
    this.attributes = attributes;
  }

  @JsonSerialize(using = AttributeSerializer.class)
  public List<Attribute> getAttributesList() {
    return attributes;
  }

  @JsonDeserialize(using = AttributeDeserializer.class)
  public void setAttributesList(List<Attribute> attributes) {
    this.attributes = attributes;
  }

似乎即使我自己没有覆盖集合，反序列化也会在底层执行，从而触发这个问题。解决方案是改变与反序列化器相关联的setter，这样它就会清除列表并添加所有内容，而不是覆盖它:

  @JsonDeserialize(using = AttributeDeserializer.class)
  public void setAttributesList(List<Attribute> attributes) {
    this.attributes.clear();
    this.attributes.addAll(attributes);
  }

检查所有你给sonEntities赋值的地方。您所引用的链接明确指出了创建一个新的HashSet，但您在重新分配该集合时可能会遇到此错误。例如:

public void setChildren(Set<SonEntity> aSet)
{
    this.sonEntities = aSet; //This will override the set that Hibernate is tracking.
}

通常在构造函数中只需要“新建”一次集合。每当您想要向列表中添加或删除一些内容时，您都必须修改列表的内容，而不是分配一个新的列表。

添加子代:

public void addChild(SonEntity aSon)
{
    this.sonEntities.add(aSon);
}

移除儿童:

public void removeChild(SonEntity aSon)
{
    this.sonEntities.remove(aSon);
}