`FetchType` is an enumeration in the Java Persistence API (JPA) that is used to define the fetching strategy for associations (relationships) between entities in a relational database.

There are two main values for FetchType:

- `FetchType.EAGER`: the association is loaded immediately when the owning entity is loaded.
- `FetchType.LAZY`: the association is not loaded unless it is explicitly accessed.

This rule raises an issue when the `fetch` argument is explicitly set to `FetchType.EAGER`.

== Why is this an issue?

Using `FetchType.EAGER` can lead to inefficient data loading and potential performance issues.
Eager Loading initializes associated data on the spot, potentially fetching more data than needed.

== How to fix it

Remove or replace `FetchType.EAGER` with `FetchType.LAZY` in JPA annotations.

=== Code examples

==== Noncompliant code example

[source,java,diff-id=1,diff-type=noncompliant]
----
@OneToMany(mappedBy = "parent", fetch = FetchType.EAGER) // Noncompliant
private List<ChildEntity> children;

@OneToMany(mappedBy = "child", fetch = FetchType.EAGER) // Noncompliant
private List<ParentEntity> parents;
----

==== Compliant solution

[source,java,diff-id=1,diff-type=compliant]
----
@OneToMany(mappedBy = "parent", fetch = FetchType.LAZY) // Compliant
private List<ChildEntity> children;

@OneToMany(mappedBy = "child") // Compliant
private List<ParentEntity> parents;
----

== Resources

=== Documentation

* https://docs.oracle.com/javaee/7/api/javax/persistence/FetchType.html[Java EE 7 API - FetchType]