This is a difficult point of view to take when confronting Julia and Ophelia in these texts. This is because there is very little proof to suggest that Julia is a weak character. It could be said that she is morally corrupt because of the way that Winston fantasises about her and she clearly is used to represent sexual temptation. Note how this is suggested in the following quote:
The girl with dark hair was coming towards them across the field. With what seemed a single movement she tore off her clothes and flung them disdainfully aside.
However, the problem with this argument is that what Julia represents with her sexuality is a kind of freedom that Winston finds desperately appealing because of the way it defies the Party and its attempted control of all aspects of the lives of its citizens.
As for Ophelia, the opposite is true. She is on the one hand very clearly a weak character who is used and abused by the male characters in her life. However, it is difficult to see how she could be viewed as morally corrupt. In Act II scene 3, for example, she meekly kowtows to her father's command to firstly tell her what she was discussing with her brother and secondly to never see Hamlet again, in spite of clearly loving Hamlet, she yields, merely saying "I shall obey, my lord." There is no evidence that she is willing to put up a fight for Hamlet. There is little suggestion however that she is morally corrupt, however. Hamlet may tell her to get to a "nunnery," but this is more about his own anger and issues and need to find a target than any real suggestion that Ophelia is immoral.