One Method, Two Regions

Four lines, and each one puts something in a different place.

java

void process() {
    int count = 3;
    String label = "total";
    List<String> rows = new ArrayList<>();
    rows.add(label);
}

Where each thing in the method lives
Thing	Lives	Gone when
`count`, holding 3	The stack frame	`process()` returns
`label`, holding an address	The stack frame	`process()` returns
The string `"total"`	The heap, in the pooled area	Effectively never, while the class is loaded
`rows`, holding an address	The stack frame	`process()` returns
The `ArrayList` object	The heap	Nothing can reach it any more

Three of the five are variables, and all three vanish together when the frame is discarded. Neither of the two objects vanishes at that moment — they become unreachable, which is a different thing and happens first.

What to notice: nothing in the method decided when the list would be freed. The frame going away only removed the last thing pointing at it.

Java
JVM
Garbage Collection