java.lang.ClassCastException: com.model.Image cannot be cast to java.lang.String

Question

I am getting the class cast Exception as

java.lang.ClassCastException: com.model.Image cannot be cast to java.lang.String

Below is my function to get the Data from an MySQL table created by an Entity Class of JPA

public List<Image> complete(String fileName) 
{
    List<Image> queryResult = new ArrayList<Image>();
    System.out.println("File Name is : "+fileName);
    if (allImages == null) 
    {
        System.out.println("Yeah I am coming here"+allImages);          
        allImages = imageFacade.findAll();
    }       
    allImages.removeAll(servicesWithImage.getImage());
    for (Image image : allImages) 
    {
        if (image.getFileName().toLowerCase().contains(fileName.toLowerCase())) 
        {
            queryResult.add(image);
        }
    }

    return queryResult;
}

I have defined the allImages globally as

private List<Image> allImages;

The above complete method I am calling from an p:autoComplete of Primefaces which is

<p:autoComplete forceSelection="true" 
                minQueryLength="3" 
                value="#{servicesMB.image}" 
                label="#{msgs.image}" 
                required="true" 
                var="image"
                itemLabel="#{image.fileName}" 
                itemValue="#{image}" 
                completeMethod="#{servicesMB.complete}" 
                dropdown="true" />

The findAll method in complete method is shown below :

public List<T> findAll() 
{
    CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
    cq.select(cq.from(entityClass));
    return em.createQuery(cq).getResultList();
 }

If I put the Print Statement in complete method I am getting what all the required data but the data is not shown on p:autoComplete and also I am getting the ClassCastException

I will edit my above complete method with print statements which something looks like

public List<Image> complete(String fileName) 
{
    List<Image> queryResult = new ArrayList<Image>();
    if (allImages == null) 
    {
        System.out.println("I am in If Condition");
        allImages = imageFacade.findAll();
        System.out.println("The Value of allImages : "+allImages);
    }
    System.out.println("Getter function servicesWithImage"+servicesWithImage.getImage());
    allImages.removeAll(servicesWithImage.getImage());
    System.out.println("allImages after removeAll method"+allImages);

    for (Image image : allImages) 
    {   

        if (image.getFileName().toLowerCase().contains(fileName.toLowerCase())) 
        {   
            queryResult.add(image);
        }
    }
    System.out.println("At the End The Value of queryResult"+queryResult);
    return queryResult;
}

My Output(Shown only for method) :

02:58:56,104 INFO  [stdout] (http-localhost-127.0.0.1-8080-5) I am in If Condition
02:58:56,121 INFO  [stdout] (http-localhost-127.0.0.1-8080-5) The Value of allImages :   [services_2.jpg, services_3.jpg]
02:58:56,122 INFO  [stdout] (http-localhost-127.0.0.1-8080-5) Getter function servicesWithImage[]
02:58:56,122 INFO  [stdout] (http-localhost-127.0.0.1-8080-5) allImages after removeAll method[services_2.jpg, services_3.jpg]
02:58:56,123 INFO  [stdout] (http-localhost-127.0.0.1-8080-5) At the End The Value of  queryResult[services_2.jpg, services_3.jpg]
02:58:56,130 SEVERE [javax.enterprise.resource.webcontainer.jsf.context] (http-localhost-127.0.0.1-8080-5) 
java.lang.ClassCastException: com.model.Image cannot be cast to java.lang.String

Help...

Answer 1

Probably is due to the autocomplete.

The autocomplete is like selects, it can't manage objects by itself, needs a converter, and this converter, must be able to convert Image object to a String, and convert this String to the Image again.

You can see a detailed explanation here https://stackoverflow.com/a/8001418/4253629]1