#2444 - exists and findCount queries produce NPE on entity defined with IdClass - SqlTreeProperties.add(SqlTreeProperties.java:38)

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptor.java

@@ -208,6 +208,7 @@ public class BeanDescriptor<T> implements BeanType<T>, STreeType, SpiBeanType {
   private final EntityBean prototypeEntityBean;
 
   private final IdBinder idBinder;
+  private final String idSelect;
   private String idBinderInLHSSql;
   private String idBinderIdSql;
   private String deleteByIdSql;
@@ -349,6 +350,23 @@ public class BeanDescriptor<T> implements BeanType<T>, STreeType, SpiBeanType {
         propertiesIndex[i] = propMap.get(ebi.getProperty(i));
       }
     }
+    idSelect = initIdSelect();
+  }
+
+  String initIdSelect() {
+    if (idProperty != null && !idProperty.name().equals("_idClass")) {
+      return idProperty.name();
+    } else if (entityType == EntityType.EMBEDDED) {
+      return null;
+    } else {
+      StringJoiner sj = new StringJoiner(",");
+      for (BeanProperty prop : propertiesNonMany) {
+        if (prop.isImportedPrimaryKey()) {
+          sj.add(prop.name());
+        }
+      }
+      return sj.toString().intern();
+    }
   }
 
   public boolean isJacksonCorePresent() {
@@ -3011,6 +3029,10 @@ public class BeanDescriptor<T> implements BeanType<T>, STreeType, SpiBeanType {
     return idProperty;
   }
 
+  public String idSelect() {
+    return idSelect;
+  }
+
   /**
    * Return true if this bean should be inserted rather than updated.
    *

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptorElement.java

@@ -23,6 +23,11 @@ abstract class BeanDescriptorElement<T> extends BeanDescriptor<T> {
     this.elementHelp = elementHelp;
   }
 
+  @Override
+  String initIdSelect() {
+    return null;
+  }
+
   private String shortName(String name) {
     int pos = name.lastIndexOf('.');
     if (pos > 1) {

ebean-core/src/main/java/io/ebeaninternal/server/querydefn/DefaultOrmQuery.java

@@ -586,9 +586,9 @@ public final class DefaultOrmQuery<T> extends AbstractQuery implements SpiQuery<
    */
   @Override
   public void setSelectId() {
-    // clear select and fetch joins..
+    // clear select and fetch joins
     detail.clear();
-    select(beanDescriptor.idBinder().getIdProperty());
+    select(beanDescriptor.idSelect());
   }
 
   @Override