PDFUnit contains error messages in English and German. The operating system's language is detected at runtime and used for error messages. If a different language is required for PDFUnit, the language has to be set for the Java process. It's not necessary to reconfigure the operating system, just set some JVM options when starting PDFUnit: PDFUnit comes with error messages in English and in German. During runtime the language of the operation system is detected and used in error messages. If a different language is desired for PDFUnit, the language has to be set for the Java process. It's not necessary to re-configure the operating system to do this: just set the JVM language options when starting PDFUnit:

// JVM start options:

-Duser.language=de -Duser.country=DE
-Duser.language=es -Duser.country=ES

Alternatively, set the required options in the environment variable _JAVA_OPTIONS.

// Environment setting for Windows:
set _JAVA_OPTIONS=-Duser.language=de -Duser.country=DE

// Environment setting for Unix:
export _JAVA_OPTIONS=-Duser.language=de -Duser.country=DE

Setting this environment variable affects all subsequent Java applications until it is reset. When the options are set in a script, global settings stay unchanged.