java.lang.ClassCastException: java.math.BigInteger cannot be cast to model.APRecord

Question

My model class:

    public class APRecord extends AbstractAPRecord implements ARecord {

    private BigInteger autoID;
    private String agentG;
    private AMMRecord mAId;
    private String aId = null;
    //getters and setters

I have a DAO method:

    public ScrollableResults getPRecord(StatelessSession statelessSession throws UnsupportedEncodingException{
   Criteria crit = statelessSession.createCriteria(APRecord.class, "apr");
   crit.createAlias("mAId", "aID", Criteria.INNER_JOIN);

   ProjectionList projList = Projections.projectionList();
    projList.add(Projections.property("aID.id"));
    projList.add(Projections.property("pName"));
    projList.add(Projections.property("kNum"));

     crit.setProjection(Projections.distinct(projList));


    return crit.scroll(ScrollMode.FORWARD_ONLY);
}

This gives an error:

    java.lang.ClassCastException: java.math.BigInteger cannot be cast to    mil.dod.netops.hbss.aps.model.APRecord 
    at          mil.dod.netops.hbss.aps.persist.hibernate.ApDAOTest.testFilteredPRecords(ApDAOTest.java:347) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at junit.framework.TestCase.runTest(TestCase.java:168) 
    at org.unitils.UnitilsJUnit3.runTest(UnitilsJUnit3.java:111) 
    at junit.framework.TestCase.runBare(TestCase.java:134) 
    at org.unitils.UnitilsJUnit3.runBare(UnitilsJUnit3.java:76) 
    at junit.framework.TestResult$1.protect(TestResult.java:110) 
    at junit.framework.TestResult.runProtected(TestResult.java:128) 
    at junit.framework.TestResult.run(TestResult.java:113) 
    at junit.framework.TestCase.run(TestCase.java:124) 
    at junit.framework.TestSuite.runTest(TestSuite.java:232) 
    at junit.framework.TestSuite.run(TestSuite.java:227) 
    at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83) 
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) 
    at         org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

I want scrollable Results back. It worked fine when I had addOrder but it didn't return me distinct results, hence the distinct query. Can someone help me fix this error?

Update: My test

  ScrollableResults results = amDAO.getPRecords(statelessSession);

    List<APRecord> pList = new ArrayList<APRecord>();
    while (results.next()){
        APRecord aPRecord = (APRecord) results.get(0); //error occurs here
        pList.add(aPRecord);
    }

Why do you want to add property "aID.id" instead of just "aID"? I guess it will solve your problem. — PatNowak
– PatNowak, Commented Aug 13, 2015 at 18:22
@Pipes there's an inner join. id is in the class AMMRecord. That's not a solution. — Jay
– Jay, Commented Aug 13, 2015 at 18:38

JB Nizet · Accepted Answer · 2015-08-13 19:20:19Z

0

The exception is caused by the line

APRecord aPRecord = (APRecord) results.get(0);

You're casting the first element of the current row of the resultset to APRecord, and it's not an APRecord, but a BigInteger, as the exception shows. And it's normal, since your query, due to the projections, returns rows containing three objects:

the ID of the AMMRecord associated with the APRecord
the pName of the the APRecord
the kNum of the APRecord

If the goal of the query is to return instances of APRecord, it should not have projections.

answered Aug 13, 2015 at 19:20

JB Nizet

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6 Comments

Jay Over a year ago

Before my DAO method had crit.addOrder( Order.asc("pName") );crit.addOrder( Order.asc("kNum") ); but it returned duplicated records. So I did a projection for which the query works in sql. Is there any way to get the actual scrollable distinct results without using projection?

JB Nizet Over a year ago

If the entity only contains the fields you're showing us, then the query shouldn't return duplicate records. But whatever. You can use projections, but just realize that what you'll get is not instances of APRecord.

Jay Over a year ago

the query returns duplicate for the id. that's why I used projections, but I need actual scrollable results. I'm not sure how to go by doing that.

JB Nizet Over a year ago

It's simple: results.get(0) is the AMMRecord ID, result.get(1) is the pName, results.get(2) is the kNum. What's the problem?

Jay Over a year ago

I did a return crit.setResultTransformer(Transformers.aliasToBean(APRecord.class)).scroll(ScrollMode.FORWARD_ONLY); for which my test returns null.

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