#1804 - Kotlin: Generating collection with wildcard type - Get error BeanNotRegisteredException: Error with association to [null] from [...Foo.manyProperty]. Is null registered?

src/test/java/org/tests/o2m/OmBasicChild.java

@@ -0,0 +1,50 @@
+package org.tests.o2m;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+import javax.persistence.Version;
+
+@Entity
+public class OmBasicChild {
+
+  @Id
+  private long id;
+
+  private final String name;
+
+  @ManyToOne
+  private final OmBasicParent parent;
+
+  @Version
+  private long version;
+
+  public OmBasicChild(String name, OmBasicParent parent) {
+    this.name = name;
+    this.parent = parent;
+  }
+
+  public long getId() {
+    return id;
+  }
+
+  public void setId(long id) {
+    this.id = id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public OmBasicParent getParent() {
+    return parent;
+  }
+
+  public long getVersion() {
+    return version;
+  }
+
+  public void setVersion(long version) {
+    this.version = version;
+  }
+}

src/test/java/org/tests/o2m/OmBasicParent.java

@@ -0,0 +1,60 @@
+package org.tests.o2m;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.OneToMany;
+import javax.persistence.Version;
+import java.util.List;
+
+import static javax.persistence.CascadeType.ALL;
+
+@Entity
+public class OmBasicParent {
+
+  @Id
+  private long id;
+
+  private final String name;
+
+  @Version
+  private long version;
+
+  /**
+   * Not really sensible Java code here but Kotlin can generate
+   * a collection type that looks like this
+   */
+  @OneToMany(cascade = ALL, mappedBy = "parent")
+  private List<? extends OmBasicChild> children;
+
+  public OmBasicParent(String name) {
+    this.name = name;
+  }
+
+  public long getId() {
+    return id;
+  }
+
+  public void setId(long id) {
+    this.id = id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public long getVersion() {
+    return version;
+  }
+
+  public void setVersion(long version) {
+    this.version = version;
+  }
+
+  public List<? extends OmBasicChild> getChildren() {
+    return children;
+  }
+
+  public void setChildren(List<? extends OmBasicChild> children) {
+    this.children = children;
+  }
+}

src/test/java/org/tests/o2m/TestOneToManyWildcard.java

@@ -0,0 +1,35 @@
+package org.tests.o2m;
+
+import io.ebean.DB;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class TestOneToManyWildcard {
+
+  @Test
+  public void test() {
+
+    OmBasicParent parent = new OmBasicParent("p1");
+    OmBasicChild c1 = new OmBasicChild("c1", parent);
+    OmBasicChild c2 = new OmBasicChild("c2", parent);
+
+    DB.save(parent);
+    DB.saveAll(Arrays.asList(c1, c2));
+
+    // we can't add to this in Java but Kotlin can
+    //parent.getChildren().add(c1);
+
+    // exercise
+    final OmBasicParent found = DB.find(OmBasicParent.class)
+      .where().idEq(parent.getId())
+      .findOne();
+
+    assertThat(found).isNotNull();
+    assertThat(found.getChildren()).hasSize(2);
+
+    DB.delete(parent);
+  }
+}