When the protesters congregate — and they often do in Indonesia’s rollicking young democracy — the street-food vendor knows to wheel his bicycle to the action. Protesters need to eat. And what better fuel for dissent than plump fish dumplings?

For more than a week now, as thousands of Indonesians have called for the nation’s lawmakers to reduce lavish spending at a time of economic hardship, Wiyono has strapped a wooden box filled with dumplings to the back of his bicycle and has pedaled more than an hour from a northern slum to a central protest area in Jakarta.

The sprawling capital of a sprawling nation, Jakarta is sinking into the Java Sea, its groundwater sucked dry and rivers overrun by its millions of residents. The income divide is yawning wider between the elite, who travel in air-conditioned SUVs to luxury malls, and other residents, who from motorcycles inhale exhaust while stuck in the city’s traffic jams. The middle class of Indonesia, the world’s fourth most populous nation, is shrinking. Youth unemployment has exceeded 16 percent in a country that should be enjoying a demographic dividend, with a swell of university graduates trying to find jobs.

Such concerns are driving the current round of protests. A generation ago, Indonesians rallied in the capital to topple a longtime dictator. Since then, they have pushed, sometimes violently, for elected presidents to address their disparate demands. They have been met with violence, too, as the nation’s security forces rely on old tactics to dissuade the demonstrations.