The type xx does not define xx(xx) that is applicable here

java代码编译报错The type MethodRefTest does not define toString(Object) that is applicable here

在java8中使用方法引用（method references）特性中的Reference to an instance method of an arbitrary object of a particular type用法时，编译器报出上述错误

import java.util.function.Function; public class Test01 { public static void main(String[] args) { Function<String, String> f1 = String::toString; Function<Object, String> f2 = String::toString; //Compilation error Function f3 = String::toString; //Compilation error } }

错误原因：没有使用泛型、或者泛型指定错误。改成像上述例子中的第一种写法即可

参考帖子：https://stackoverflow.com/questions/27344097/reference-to-an-instance-method-of-an-arbitrary-object-of-a-particular-type-n