I am trying to get my finish page from the flow to go to different places based on the result of a decision in the flow. If a case is created in the flow, the finish location is the case, if it's not created, the finish location is a custom object called Conversation__c. What's happening is that it is giving an error

System.NullPointerException: Attempt to de-reference a null object
Class.CaseFlowController.getFinishPage: line 34, column 1

And I don't know how to fix this. Line 34 is the if statement in getFinishPage().

Code for the Controller:

public class CaseFlowController {

    private final Conversation__c conv;
    public CaseFlowController(ApexPages.StandardController stdController) {
    	this.conv = (Conversation__c)stdController.getRecord();
    }


	//Calls referenced Flow below
	public Flow.Interview.createCasefromConversation createCasefromConversation { get; set; }
	//Gets Id of variables below from flow
	public String getconversationID() {
		if (createCasefromConversation==null){
		 return '';
		}else{ 
			System.Debug('ConversationID:' + createCasefromConversation.conversationId);
			return createCasefromConversation.conversationId;
		}
		
	}
	

	public String getcaseID() {
		if (createCasefromConversation==null) {
			return '';
			} else {
				System.Debug('CaseId:' + createCasefromConversation.createdCaseId);
				return createCasefromConversation.createdCaseId;
		}
	}
	
	//Used for Flow finish location
	public PageReference getFinishPage(){ 
		if(createCasefromConversation.createdCaseId == ''){	
			PageReference p = new PageReference('/' + getconversationID());
			p.setRedirect(true);
			system.debug('Page conversation' + p);
			return p;
			
		}else {
			PageReference p = new PageReference('/' + getcaseID());
			p.setRedirect(true);
			system.debug('Page case' + p);
			return p;
		}
	}

}

Here is the code for the Visual Force Page:

<apex:page StandardController="Conversation__c" extensions="CaseFlowController">
   <flow:interview name="createCasefromConversation" interview="{!createCasefromConversation}" finishLocation="{!FinishPage}" />

</apex:page>

Any help would be greatly appreciated.

Thanks,

Chris