我意識到Java 8仍然在測試版，但是這一點讓我很奇怪：

public class Fields> {

public Fields(Set columns) {

// A sample column used to find the universe of the enum of Columns.

C sampleCol = columns.iterator().next();

// Java 8 needs a cast here.

Set allColumns = EnumSet.allOf((/*Class)*/ sampleCol.getClass());

// ... there's more to this that I've deleted.

}

}

錯誤讀取：

error: incompatible types: inferred type does not conform to equality constraint(s)

Set allColumns = EnumSet.allOf(sampleCol.getClass());

inferred: C

equality constraints(s): C,CAP#1

where C is a type-variable:

C extends Enum declared in class Test.Fields

where CAP#1 is a fresh type-variable:

CAP#1 extends Enum from capture of ? extends Enum

這是Java 8的一個bug還是新功能？

總結

以上是生活随笔為你收集整理的java enum in class_Java 8需要一个转换,而Java 7没有 – enum.getClass/getDeclaringClass的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。