Methods are provided for extracting reference patterns in JAVA and depicting the same. The extracted and depicted reference patterns may be used to interactively and selectively explore data structures, and to identify and solve memory leaks. A method for extracting reference relationships among objects corresponding to a running program includes the step of designating a starting set of objects. The starting set of objects is partitioned into subsets of objects grouped by class. A recursive operation is applied to each of the starting subsets. The recursive operation includes the step of, given a subset of objects, identifying a second set of objects. The second set includes all objects that refer to at least one object in the subset when a direction of reference terminates at the starting set. Alternatively, the second set includes all objects that are referred to by at least one object in the subset when the direction of reference originates from the starting set. The recursive operation also includes the step of partitioning the second set into new subsets of objects grouped by class. The recursive operation is applied to each of the new subsets until a predefined depth is reached.