Intro Local Variable Out Defined In An Enclosing Scope Must Be Final Or Effectively Final

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Intro Local Variable Out Defined In An Enclosing Scope Must Be Final Or Effectively Final

這篇介紹Local Variable Out Defined In An Enclosing Scope Must Be Final Or Effectively Final。

Example

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在stream().forEach()方法內使用一個外部的參數時，會出現以下
Local variable out defined in an enclosing scope must be final or effectively final 錯誤訊息。

list.stream().forEach(x -> {
	try {
		gen(out);
	} catch (Exception e) {
	}
});

在gen(out); 這行會出現以上錯誤訊息。

解決方法為
final JspWriter out1  = out;
list.stream().forEach(x -> {
	try {
		gen(out1);
	} catch (Exception e) {
	}
});