Used in context denoting time, the two adverbs are antonymous. ‘cái’ means ‘later than the expected time’, sometimes implying that the event in question does not go smoothly; and ‘jiù’ means ‘sooner or earlier than the expected time’.
Wǒmen bā diǎn kāihuìtā bā diǎn bàn cái dào.
(The meeting began at eight o’clock, but he didn’t come until eight thirty.)
Diànhuà dǎ le jǐ cì cái dǎtōng.
(Only after dialing a few times did the line go through.)
Qùle jǐ tàng cái zhǎodào jīnglǐ.
(Only after going there a few times did I see the manager.)
Nǐ zài zhèr děngdengwǒ yīhuìr jiù lái.
Wait here for a while, I’ll be back in a minute.)
Tā xué kāichēbùjǐtiān jiù xuéhuì le.
(He learned how to drive only in a few days.)
Dōngtiān xiàwǔ wǔ diǎn duō zhōng tiān jiù hēi le.
(In the winter it becomes dark a little after five o’clock.)
‘cái’ in (1a) denotes that the event of coming happens later than expected, in (1b, c), it implies that the situations described by the sentences go slowly and unsmoothly. By contrast, the adverb ‘jiù’ in (2a) indicates that the events happen earlier than expected, in (2b), ‘jiù’ signals that the situation of learning to drive occurs sooner and faster than expected.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.