The history here is far less cut and dried that with the Hawaiian Ukulele but the chordophones I am talking about have their roots in the same kinds of Portuguese Cavaquinho as the Ukulele. 

Their history starts in the 16th century when Portuguese explorers and colonists first came to the Indonesian archipelago, (particularly Timor). Though less enthusiastic that the native Hawaiians, the Cavaquinho derived instruments found their way into the local music scene and led to a local/Portuguese hybrid music style that was called Keroncong, (or Kroncong there are debates about the proper spelling?), because of the jingling style of the rhythm instruments. 

Originally the instruments used would have been standard western Cavaquinhos; or Mandolins, or even Violins, whatever the musicians could get a hold of and play, but over the years the local craftsmen started to make their own versions of particularly the Cavaquinho. The first "change" and its not really a change but a regressions was, because they didn't have the gluing technology they went with the carving the back and sides, and often the neck too, out of a single piece of wood, then there was the use of a tailpiece and floating bridge, Mandolin style, again because they couldn't glue the bridge strongly enough, and finally the musical compromise that moved the instruments, because of the common Cavaquinho tuning D~D~G~B where the two D's are the same note, to being a three course instrument, with a string either dropped, (in the case of the Cuk), or doubled into on course, (in the case of the Cak), thus creating two distinct chordophones that collectively became known as the Keronkong, (the Ukulele name was added much later), after the music they were used to play. 

The Cak

The Cak, (pronounced chack) has 4, (often steel), strings in 3 courses tuned d~d~G~B and usually multiple small sound holes. They are higher toned instrument of the pair and carved out thinner than the Cuk. 

The Cuk

The Cuk, (pronounced chook) have 3, (Nylon or gut), strings tuned g~B~E, an octave lower than the Cak and a central sound hole, (well the G is the same note on the two instruments). Both instruments are usually made as a matching pair and used in the Keroncong band with neither the music style nor the instruments themselves meant for solo work.

If you research the instrument on the Internet you will see it suggested there was some kind of major change in the instrument and style in 1880 due to the advent of the Ukulele - Really? the Ukulele wasn't that big in Hawaii at the time so how did it suddenly influence a culture thousands of miles away, (remembering the area was now under Dutch colonial rule, apart from Timor). There may have been a change, but if there was it was coincidental and the word Ukulele and its association to the Keronkong didn't come into being until the 1920's at the earliest.