[jira] Created: (CAY-1444) NPE when persisting a newly instatiated object

["Thomas Lopatic (JIRA)" <ji...@apache.org>]

NPE when persisting a newly instatiated object
----------------------------------------------

                 Key: CAY-1444
                 URL: https://issues.apache.org/jira/browse/CAY-1444
             Project: Cayenne
          Issue Type: Bug
          Components: Core Library
    Affects Versions: 3.0
            Reporter: Thomas Lopatic
            Priority: Minor


I get a NPE when persisting a newly created object. My object has an auto-increment primary key and, other than that, contains references to three more objects. Here's what it looks like.

<obj-entity name="Settings" className="xxx.Settings" lock-type="optimistic" dbEntityName="Settings">
  <obj-attribute name="name" type="java.lang.String" db-attribute-path="name"/>
</obj-entity>

<obj-relationship name="settingsCity" source="Settings" target="City" deleteRule="Nullify" db-relationship-path="settingsCity"/>
<obj-relationship name="settingsUser" source="Settings" target="User" deleteRule="Nullify" db-relationship-path="settingsUser"/>

<db-entity name="Settings" schema="xxx">
  <db-attribute name="id" type="BIGINT" isPrimaryKey="true" isGenerated="true" isMandatory="true"/>
  <db-attribute name="idCity" type="BIGINT"/>
  <db-attribute name="idUser" type="BIGINT"/>
  <db-attribute name="name" type="VARCHAR" length="50"/>
</db-entity>

<db-relationship name="settingsCity" source="Settings" target="City" toMany="false">
  <db-attribute-pair source="idCity" target="id"/>
</db-relationship>

<db-relationship name="settingsUser" source="Settings" target="User" toMany="false">
  <db-attribute-pair source="idUser" target="id"/>
</db-relationship>

I instantiate my Settings object and leave the name, settingsCity, and settingsUser object references at null. Then I commit. What then happens is that DataDomainDBDiffBuilder.buildDBDiff() returns null, because dbDiff.isEmpty() is true. This null reference then ends up in InsertBatchQuery.objectSnapshots.

So, it looks like if all members of a newly created object are null, no differences are detected. Note that I use a database-generated auto-increment primary key. So, the primary key is possibly also still null at this stage.

The null reference in InsertBatchQuery.objectSnapshots ultimately leads to the following NPE.

13:16:16,542  INFO QueryLogger:357 - INSERT INTO xxx.Settings (idCity, idUser, name) VALUES (?, ?, ?)
13:16:16,543  INFO QueryLogger:453 - *** error.
java.lang.NullPointerException
	at org.apache.cayenne.query.BatchQuery.getValue(BatchQuery.java:164)
	at org.apache.cayenne.query.InsertBatchQuery.getValue(InsertBatchQuery.java:61)
	at org.apache.cayenne.access.trans.InsertBatchQueryBuilder.getParameterValues(InsertBatchQueryBuilder.java:81)
	at org.apache.cayenne.access.jdbc.BatchAction.runAsIndividualQueries(BatchAction.java:212)
	at org.apache.cayenne.access.jdbc.BatchAction.performAction(BatchAction.java:91)
	at org.apache.cayenne.access.DataNodeQueryAction.runQuery(DataNodeQueryAction.java:87)
	at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:269)
	at org.apache.cayenne.access.DataDomainFlushAction.runQueries(DataDomainFlushAction.java:226)
	at org.apache.cayenne.access.DataDomainFlushAction.flush(DataDomainFlushAction.java:144)
	at org.apache.cayenne.access.DataDomain.onSyncFlush(DataDomain.java:824)
	at org.apache.cayenne.access.DataDomain$2.transform(DataDomain.java:791)
	at org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:850)
	at org.apache.cayenne.access.DataDomain.onSync(DataDomain.java:788)
	at org.apache.cayenne.access.DataContext.flushToParent(DataContext.java:1106)
	at org.apache.cayenne.access.DataContext.commitChanges(DataContext.java:1045)
[...]

Thomas


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