MVEL 使用模板,当并发量大的时候, 报错 [Error: no context]

Caused by: java.lang.RuntimeException: no context
at org.mvel2.ParserContext.makeVisible(ParserContext.java:684)
at org.mvel2.ParserContext.addVariable(ParserContext.java:477)
at org.mvel2.ast.TypedVarNode.(TypedVarNode.java:64)
at org.mvel2.compiler.AbstractParser.procTypedNode(AbstractParser.java:1402)
at org.mvel2.compiler.AbstractParser.nextToken(AbstractParser.java:784)
at org.mvel2.compiler.AbstractParser.nextTokenSkipSymbols(AbstractParser.java:188)
at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:156)
at org.mvel2.MVEL.compileExpression(MVEL.java:816)
at org.mvel2.templates.res.CompiledExpressionNode.(CompiledExpressionNode.java:41)
at org.mvel2.templates.TemplateCompiler.compileFrom(TemplateCompiler.java:209)
... 22 more

http://jjw.iteye.com/blog/706034