Eg in NumberFormat.format(Object, StringBuffer, FieldPosition)

```
        if (number instanceof Long || number instanceof Integer ||
            number instanceof Short || number instanceof Byte ||
            number instanceof AtomicInteger || number instanceof AtomicLong ||
            (number instanceof BigInteger &&
             ((BigInteger)number).bitLength() < 64)) {
            return format(((Number)number).longValue(), toAppendTo, pos);
        } else if (number instanceof Number) {
            return format(((Number)number).doubleValue(), toAppendTo, pos);
        } else {
            throw new IllegalArgumentException("Cannot format given Object as a Number");
        }
```
can be simplified to:
```
        return switch (number) {
            case Long l -> format(l.longValue(), toAppendTo, pos);
            case Integer i -> format(i.longValue(), toAppendTo, pos);
            case Short s -> format(s.longValue(), toAppendTo, pos);
            case Byte b -> format(b.longValue(), toAppendTo, pos);
            case AtomicInteger ai -> format(ai.longValue(), toAppendTo, pos);
            case AtomicLong al -> format(al.longValue(), toAppendTo, pos);
            case BigInteger bi when bi.bitLength() < 64 -> format(bi.longValue(), toAppendTo, pos);
            case Number n -> format(n.doubleValue(), toAppendTo, pos);
            default -> throw new IllegalArgumentException("Cannot format given Object as a Number");
        };
```