Getting object as a result

General
1

In some custom event I put an object into map, but when I get this map as a response I get the following error:

Exception in thread "pool-1-thread-1" java.lang.ClassCastException: java.util.HashMap cannot be cast to com.list.models.Aua

This line causes it:

Aua aua = (Aua) result.get("last");

However, if I just see what response map contains, I am able to see some object with needed properties
I have a public constructor for this object.
Why do the casting causes error? Thank you

2

Try to add the following line before any calls to table ‘Aua’:

Backendless.Data.mapTableToClass('Aua', Aua.class);

If it doesn’t help - provide your Aua class here.

3 
public class Test {
private String objectId;
private java.util.Date updated;
private String testProperty;
private java.util.Date created;
private String ownerId;
 



 



public String getObjectId()
{
return this.objectId;
}
 



public java.util.Date getUpdated()
{
return this.updated;
}
 



public String getTestProperty()
{
return this.testProperty;
}
 



public java.util.Date getCreated()
{
return this.created;
}
 



public String getOwnerId()
{
return this.ownerId;
}
 



 



public void setObjectId( String objectId )
{
this.objectId = objectId;
}
 



public void setUpdated( java.util.Date updated )
{
this.updated = updated;
}
 



public void setTestProperty( String testProperty )
{
this.testProperty = testProperty;
}
 



public void setCreated( java.util.Date created )
{
this.created = created;
}
 



public void setOwnerId( String ownerId )
{
this.ownerId = ownerId;
}
 



public Test save()
{
return Backendless.Data.of( Test.class ).save( this );
}
 



public Long remove()
{
return Backendless.Data.of( Test.class ).remove( this );
}
 



public static Test findById( String id )
{
return Backendless.Data.of( Test.class ).findById( id );
}
 



public static Test findFirst()
{
return Backendless.Data.of( Test.class ).findFirst();
}
 



public static Test findLast()
{
return Backendless.Data.of( Test.class ).findLast();
}
 



public Test(){}
 



}

Here is my business logic function:

List<Test> list = null; 
HashMap<String, Object> result = new HashMap<String, Object>(); 
 
@Override 
public Map handleEvent( RunnerContext context, Map eventArgs ) 
{ 
 Backendless.Data.mapTableToClass("Test", Test.class); 
 BackendlessCollection<Test> response = Backendless.Persistence.of( Test.class ).find(); 
 list = response.getData(); 
 Test test = list.get(list.size() - 1); 
 
 result.put("last", test); 
 
 return result; 
 
}

Here is how I get my object:

Test test = (Test) result.get("last"); 
System.out.println(test.getTestProperty());

my Test table has only 1 property (testProperty)

4

Where does “Aua” come from then?

5

Sorry, I forgot to mention that I made a test class for this exact test, because that Aua class had too much properties. Both of them thow cast exception

6

Does the class belong to a package?

7

yes. I thought I was missing something in a class defenition.

8

Try to change

HashMap<String, Object> result = new HashMap<String, Object>();

to

HashMap<String, Test> result = new HashMap<String, Test>();

in your business logic code.

9

Just to make sure I understand: you have a custom event which returns the Test object in that hashmap. Then you invoke the custom event from the client app and that’s when the error occurs?

10

@AleksandrNavara Unfortunately, it did not help

@MarkPiller Yes, it is absolutely correct

11

Did you replicate the Test class on the client side the same way? (in other words, are they identical between server-code and client-code?)

Do you have the Backendless.Data.mapTableToClass call on the client-side?

12

Thank you a lot, it worked!