are you sure that "Fully Justified" text is the best way to format this document?
Fully Justified may be proper in books or in newspaper print, but in other documents, like reports, blogs, essays, etc, such formatting can be quite difficult to read, and often produces anomalies. Have a look at the two examples I have created, (using text from the Forum Policy link on the left), to see the difference between fully justified and left justified text in Word;
To my mind the left justified version seems better, and easier to read.
However, if you want to or need to stay with Fully Justified, there are things you can try;
1] For those lines, usually at the end of a paragraph, where just a few words stretch across the whole line, make them Left Justified. You would have to experiment, for example, moving that last line down temporarily to break it away from the paragraph before left justifying it.
2] The URL link can be displayed in a shortened version with a Display Name. Highlight the link, goto Insert > Hyperlink, (in Word), and type in "Text to display".
3] If that doesn't work, then just reformat the paragraph so that the line in question is on its own with a part paragraph above and the remainder below, with empty lines separating them.
I hope there's something there that helps.