How to retrieve child object values using SOAP service through groovy?

Content

Hi Team,

I am trying to retrieve a value from contract child object using SOAP service in servicerequest object.Below is the format I have used to give parameters but it is throwing cast exception.

If anyone knows what is the mistake in the below script please let me know to resolve.

Exception:
oracle.binding.expr.ServiceInvocationException: JBO-29000: Unexpected exception caught: java.lang.ClassCastException, msg=java.lang.String cannot be cast to [Ljava.lang.Object;

Version

20D

Code Snippet

def contractid = ContractNumber_Obj_c?.ContractId_c
def assetid = IBAssetId
//println("contractid : " + contractid)

def findCriteria =
[  
    fetchStart :0,
    fetchSize :-1,
	
    filter:
    [      
      group:      
      [[
        item:
        [[
          upperCaseCompare :'false',
          attribute :'ContractId',