<i18n dev> Scanner and NumberFormatProvider

[Naoto Sato]

Hi Umaoka-san,

Yeah, that looks like a bug to me. Can you please file it, as I wasn't 
aware of it being reported.

Naoto

On 10/13/17 10:39 AM, Yoshito Umaoka wrote:
> Hello,
> 
> I received a problem report from an ICU4J consumer who uses ICU4J Locale SPI module.
> ICU NumberFormatProvider returns a class - com.ibm.icu.impl.jdkadapter.NumberFormatICU which extends java.text.NumberFormat.
> 
> The ICU4J locale SPI user found the ICU provider causes an issue when he uses Scanner. I can reproduce the problem on my environment as well. The exception call stack shows -
> 
> Exception in thread "main" java.lang.ClassCastException: com.ibm.icu.impl.jdkadapter.NumberFormatICU cannot be cast to java.text.DecimalFormat
> 	at java.util.Scanner.useLocale(Scanner.java:1186)
> 	at java.util.Scanner.<init>(Scanner.java:540)
> 	at java.util.Scanner.<init>(Scanner.java:563)
> 	at test.ScannerTest.main(ScannerTest.java:11)
> 
> Below is the location in Scanner.java
> 
>      public Scanner useLocale(Locale locale) {
>          if (locale.equals(this.locale))
>              return this;
> 
>          this.locale = locale;
>          DecimalFormat df =
>              (DecimalFormat)NumberFormat.getNumberInstance(locale);
>          DecimalFormatSymbols dfs = DecimalFormatSymbols.getInstance(locale);
> 
> So the implementation blindly cast NumberFormat instance returned by getNumberIntance(Locale) to DecimalFormat.
> I thought I reported this issue before. Are you aware of this issue? Maybe, I forgot to file a bug when I investigated this earlier in this year, because I could not find it in java bug.
> 
> -Yoshito
>