Endless stamping of militarised boot on the neck of any that objected?

To clarify further, modern Indonesia includes some 17,000 islands that historically included almost as many different cultural variations.

The Dutch East Indies included (according to the Dutch) most of those islands and more.

The spice trade was a major revenue stream, so much so that one activity included destroying alternative sources of certain spices on islands that weren't part of the Dutch industrial spice pipeline - to avoid any chance of rivals from France, Germany, England, Spain, etc. sneaking in and getting their own cuttings to start rival plantations.

The VOC (under that name (or another later?)) were active in the region from 1600 - 1940 (ish) when the Japanese swept through and seized oil supplies, etc.

As for the rest; slavery, starting civil wars to divide and conquer, several waves of outright direct warring, destruction of libraries and buildings from local empires that went back centuries, .. the usual fun and games of colonial powers.

https://en.wikipedia.org/wiki/Dutch_East_Indies gives a bief outline.

The Dutch Rubber slave plantations were the ones with all the fun "Meet your literally impossible quota or we chop off your child's hands" rules, and other utterly ruthless and disgusting methods of keeping control.