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Quirk: BigDecimal equals vs compareTo #92

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Quirk: BigDecimal equals vs compareTo#92
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dailyQueued for the daily learning PRtrack:quirksSurprising behaviour and classic pitfalls

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@mperor
mperor
opened on Oct 22, 2026

Goal: show why new BigDecimal("2.0").equals(new BigDecimal("2.00")) is false.

Show:

  • equals compares scale, compareTo does not
  • consequences: HashSet keeps both, TreeSet keeps one
  • new BigDecimal(0.1) vs BigDecimal.valueOf(0.1); stripTrailingZeros()

Where: FirstSteps/src/test/java/pl/mperor/lab/java/quirk

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  1. mperor
    added
    track:quirksSurprising behaviour and classic pitfalls
    dailyQueued for the daily learning PR
    on Oct 22, 2026
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