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[Support #SJE-633108]: [udunits] ucar.units.Unit subclasses override equals( Object), but not hashCode()


> Many of the subclasses of ucar.units.Unit override equals(Object), but
> fail to override hashCode().

Thanks for bringing this to my attention.  I'll see what I can do
about fixing it ASAP.

> As a result, the hashCode() implementation
> that is inherited from Object no longer satisfies its contract, namely:
> If two objects are equal according to the equals(Object) method, then
> calling
> the hashCode method on each of the two objects must produce the same
> integer result.
> Here is an example of the contract being broken:
> Unit unit1 = UnitFormatManager.instance().parse("m/s");
> Unit unit2 = UnitFormatManager.instance().parse("m/s");
> System.out.println(unit1.equals(unit2));  // Prints "true"
> System.out.println(unit1.hashCode() == unit2.hashCode());  // Prints "false"
> As a result of this behavior, Units are not generally usable in a
> hashing container.
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Steve Emmerson

Ticket Details
Ticket ID: SJE-633108
Department: Support UDUNITS
Priority: Normal
Status: Open