On line learning or stochastic learning:
Stochastic learning occurs when the neuron weights are updated after each individual piece of data is passed through the system. The Feed Forward Neural Network therefore changes with every piece of data and is in a constant state of change during training.
Batch Learning on the other hand stores each neuron weight change when it occurs, and only at the end of each epoch does it update the weights with the net change over the training set. This means the neural network will only update once at the end of each epoch.