Java, 58 bytes
l->l.stream().map(x->java.util.Collections.frequency(l,x))
l->l.stream().map(x->java.util.Collections.frequency(l,x))
Java, 56 bytes
l->l.stream().map(x->l.stream().filter(y->y==x).count())
This only works for integers in the Integer Cache (-128 to 127, by default).