build error for expression, please check

\spring-framework\spring-expression\src\main\java\org\springframework\expre ssion\spel\ast\OpMultiply.java:28: error: unmappable charact
er for encoding GBK
* <p>If any of the operands is of a reference type, unboxing conversion (?.1.8) is performed. Then:<br>
^
1 error

FAILURE: Build failed with an exception.

Hello

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2) Post the complete error stack trace
3) From where you are getting such error? Post the source code