I'm going through this myself, so far I've found:
Put the variable into the map like you wrote:
Map<String, Object> params = new HashMap<String, Object>();
boolean examOK = false;
params.put("examOK", examOK);
ksession.startProcess("com.sample.bpmn.hello", params);
Then in the bpmn definition, you need to have the process variables (if you want a global process variable I think?):
<itemDefinition id="_examOK" structureRef="java.lang.Boolean" />
and within the process def itself (still in the .bpmn file):
<property id="examOK" itemSubjectRef="_examOK"/>
You also need the dataInput mapped to your task (within your task, that lies inside the process):
<dataInput id="_999_examOK" name="examOK" />
<inputSet>
<dataInputRefs>_999_examOK</dataInputRefs>
</inputSet>
<dataInputAssociation>
<sourceRef>examOK</sourceRef>
<targetRef>_999_examOK</targetRef>
</dataInputAssociation>
That will map it into your workItemHandler, so you can obtain it via:
Boolean examOk = (Boolean) workItem.getParameter("examOK");
I'm not 100% sure if this is the "correct" way to implement this. I'm unsure if this variable is global for all processes, for instance: what if the process is started multiple times for multiple users? Does each process implementation get its own global examOk boolean using this method?