In some cases, boxing can be source of significant performance penalty, especially in loops.
Example:
public void example() {
Long l = 12L;
needBox(l);
for (int i = 0; i < 10; i++) {
needPrimitive(l); // Loops usages considered as more often
}
}
void needPrimitive(long l) {}
void needBox(Long l) {}
New in 2018.2