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POException java.lang.ClassCastException
 

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  1. POException java.lang.ClassCastException
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    <p>I am trying to read only two column (One is Integer and other is String) from the table and get a list of the result. I am reading the table using <code>EntityManger</code> as shown in the code below. This code executes correctly and no Exception comes.</p> <pre><code>@SuppressWarnings("unchecked") public List&lt;BusinessProcessIdAndName&gt; getBusinessProcessList(int level) { List&lt;BusinessProcessIdAndName&gt; businessProcessTableList = new ArrayList&lt;BusinessProcessIdAndName&gt;(); EntityManager em = null; try { EntityManagerFactory emf = Persistence.createEntityManagerFactory(ApplicationConstants.DERBY_PERSISTENCE_UNIT_NAME); em = emf.createEntityManager(); EntityTransaction et = em.getTransaction(); et.begin(); Query query = em.createQuery("select t.businessProcessId, t.businessProcessName from BusinessProcessTable t"); businessProcessTableList = query.getResultList(); // The line below displays the correct result, The logger is basically a System.out.println logger.debug(businessProcessTableList.size()); } catch(Exception e) { logger.debug("Exception Caught while getting BP List: " + e); } return businessProcessTableList; } </code></pre> <p><code>BusinessProcessIdAndName</code> class is as below</p> <pre><code>public class BusinessProcessIdAndName { private Integer businessProcessId; private String businessProcessName; public Integer getBusinessProcessId() { return businessProcessId; } public void setBusinessProcessId(Integer businessProcessId) { this.businessProcessId = businessProcessId; } public String getBusinessProcessName() { return businessProcessName; } public void setBusinessProcessName(String businessProcessName) { this.businessProcessName = businessProcessName; } } </code></pre> <p>Then in Managed Bean I am using the result of the above code as below. Here I get the Exception </p> <blockquote> <p>java.lang.ClassCastException: [Ljava.lang.Object; incompatible with com.ewt.ewtalmutil.object.BusinessProcessIdAndName</p> </blockquote> <p>I know this Exception says that there is a mismatch in the object and they are incompatible, But I think my objects should be compatible, please tell me where I am wrong and what is the correct way to do it.</p> <pre><code>public SelectCriteriaBean () { logger.entering(CLASS_NAME); this.businessProcessLevelZeroList = new ArrayList&lt;SelectItem&gt;(); List&lt;BusinessProcessIdAndName&gt; tempBusinessProcessLevelZeroList = new BusinessProcessTableManager().getBusinessProcessList(0); // The line below also displays correct result logger.debug(tempBusinessProcessLevelZeroList.size()); // The line below gives Exception: java.lang.ClassCastException: [Ljava.lang.Object; incompatible with com.ewt.ewtalmutil.object.BusinessProcessIdAndName try { Iterator&lt;BusinessProcessIdAndName&gt; iterator = tempBusinessProcessLevelZeroList.iterator(); } catch (Exception e) { logger.debug("Exception: " + e); } while (iterator.hasNext()) { BusinessProcessIdAndName businessProcessIdAndName = new BusinessProcessIdAndName(); businessProcessIdAndName = iterator.next(); // The Exception/Error comes in the line below String businessProcessName = businessProcessIdAndName.getBusinessProcessName(); int businessProcessId = businessProcessIdAndName.getBusinessProcessId(); String businessProcessIdString = String.valueOf(businessProcessId); SelectItem item = new SelectItem(businessProcessIdString,businessProcessName); businessProcessLevelZeroList.add(item); } setBusinessProcessLevelOneListRendered(false); setAddBusinessProcessRendered(false); logger.exiting(CLASS_NAME); } </code></pre>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
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      1. POException java.lang.ClassCastException
      1. This table or related slice is empty.
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    1. COYou have two lines commented as giving the exception. Which one is it? If the first, does the logger log the exception as expected from the `catch` clause`, or does the program throw an exception? Are you sure that you counted lines correctly?
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      1. POException java.lang.ClassCastException
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    2. COThe line where you create the iterator doesn't throw that exception. The initialization of `businessProcessIdAndName` the line before you assign it to `iterator.next()` is a waste of time and space.
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      1. POException java.lang.ClassCastException
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    3. COException comes in try catch block, so the code line businessProcessIdAndName = iterator.next(); gives exception
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      1. POException java.lang.ClassCastException
      1. USSXV
 

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