Decimalformat does not work with locale

[dunham]

Number input: 10000.1654687 -> Trying to get swiss number

thousand seperator = ' (single quote)

decimal seperator = , (comma)

 

Decimals do not work (thousand sep do) -> new DecimalFormat("#,##0.#").getInstance($P{REPORT_LOCALE}).format(10000.1654687) -> 10'000.165

Decimals do not work (thousand sep do) -> new DecimalFormat("#,##0.").getInstance($P{REPORT_LOCALE}).format(10000.1654687) -> 10'000.165

Works but without proper locale ??? -> new DecimalFormat("#,##0.#").format(10000.1654687) -> 10,000.2

When I just print $P{REPORT_LOCALE} -> de_CH

What's the problem here?