RFR JDK-8200243: System error message is decoded as invalid encoding in Windows.

[Xueming Shen]

On 6/27/18, 12:39 AM, Alan Bateman wrote:
> On 27/06/2018 04:14, Xueming Shen wrote:
>> Hi,
>>
>> Please help review the change for JDK-8200243
>>
>> issue: https://bugs.openjdk.java.net/browse/JDK-8200243
>> webrev: http://cr.openjdk.java.net/~sherman/8200243/webrev
>>
>> This is a regression. The root cause is one of the change we put in 
>> jdk9 for
>> JDK-8057777 [1], which is to remove those unused vm interfaces.
>>
>> The webrev [1] indicates that the changeset added a platform 
>> dependent version of
>> GetLastErrorString(),  which uses utf8, to replace the original jvm 
>> version of
>> JVM_GetLastErrorString() (in jni_util.c).
>>
>> However the encoding of the char* interface between jvm and jdk is 
>> always
>> interpreted/specified as "native encoding". So if the platform's 
>> default encoding
>> is NOT utf-8, it never uses  utf8. This is what we have on Windows 
>> platform. The
>> fix is to use/copy-paste the "original" vm implementation in hotspot 
>> repo for
>> JVM_GetLastErrorString() (from os_windows.cpp).
> This looks okay, just not immediately clear if this links to 
> FormatMessageA or FormatMessageW.
>
Without an explicit _UNICODE and UNICODE switch it should always be "A" 
version. If we have more
time maybe I should go through the circle to simply use the "A" explicitly.

-Sherman