1. A method for classifying objects in a graph data stream, the graph data stream including a plurality of nodes that represent elements and edges that represent connections between the elements, and wherein an object in the data stream is a group of nodes together with the edges between those nodes, the method comprising: receiving a training stream of graph data, the training stream including a plurality of objects along with class labels that are associated with each of the nodes and edges of the objects; first determining discriminating sets of edges in the training stream for the class labels, wherein a discriminating set of edges is one that is indicative of the object that contains these edges having a given class label; receiving an incoming data stream of the graph data, wherein class labels have not yet been assigned to objects in the incoming data stream; second determining, based on the discriminating sets of edges, class labels that are associated with the objects in the incoming data stream; and outputting to an information repository object class label pairs based on the second determining, wherein the method is performed using a processor, wherein the first determining comprises: arranging first incoming edges of the training stream in a two-dimensional (2D) data structure, wherein rows of the 2D data structure correspond to different graphs in the training stream and columns of the 2D data structure represent different edges in the training stream; generating hash values for the edges in each row and column of the 2D data structure, the hash values being generated using a min-hash function; identifying correlated sets of edges, wherein a correlated set of edges is a set of edges relevant to a particular object in the training data, wherein a set of edges having the same min-hash value is a correlated set of edges; and assigning class labels to the correlated sets of edges to obtain the discriminating sets of edges, wherein a class label that is assigned to a particular correlated set of edges is a dominant class label of the correlated set of edges.