jBPM6 provides various predefined strategies for handling knowledge sessions. An simple example using singleton strategy is shown in https://community.jboss.org/people/bpmn2user/blog/2014/01/14/jbpm6--angularuing-grid-web-example.  It uses a single knowledge session to execute all the process instances. A different strategy ‘PerRequestRequestManager’ is used in this blog. This approach creates a new knowledge session for each request.

RuntimeManager is craeted using the strategy 'PerRequestRuntimeManager' as shown below.

A knowledge session is created for each request for performing various tasks such as process create, query and approve etc.