@Documented @Retention(value=RUNTIME) @Target(value={CONSTRUCTOR,METHOD}) public @interface SafeVarargs
除了@Target
元注释的使用限制外,还需要编译器对此注释类型实施其他使用限制; 如果方法或构造函数声明使用@SafeVarargs
注释注释,则是编译时错误,并且:
static
也不是final
的可变方法。 当这种注释类型应用于方法或构造函数声明时,鼓励编译器发出警告:
Object
和String
。 (可注释元素类型不会发生此注释类型禁止的未选中的警告。) 在运行时导致@SafeVarargs // Not actually safe! static void m(List<String>... stringLists) { Object[] array = stringLists; List<Integer> tmpList = Arrays.asList(42); array[0] = tmpList; // Semantically invalid, but compiles without warnings String s = stringLists[0].get(0); // Oh no, ClassCastException at runtime! }
ClassCastException
。 该平台的未来版本可能要求对这种不安全操作的编译器错误。
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