code: public AbstractJobVertex findVertexWithNullEdges() {
  
  		final AbstractJobVertex[] allVertices = getAllJobVertices();
  
  		for (int i = 0; i < allVertices.length; i++) {
  
  			for (int j = 0; j < allVertices[i].getNumberOfForwardConnections(); j++) {
  				if (allVertices[i].getForwardConnection(j) == null) {
  					return allVertices[i];
  				}
  			}
  
  			for (int j = 0; j < allVertices[i].getNumberOfBackwardConnections(); j++) {
  				if (allVertices[i].getBackwardConnection(j) == null) {
  					return allVertices[i];
  				}
  			}
  		}
  
  		return null;
  	}
docs: Checks if any vertex of this job graph has an outgoing edge which is set to <code>null</code>. If this is the
  case the respective vertex is returned.
  
  @return the vertex which has an outgoing edge set to <code>null</code> or <code>null</code> if no such vertex
  exists