当我显式使用另一个类中的一个类的公共函数时，为什么Java没有给我编译错误

Question

I have two classes class1, and class1Test, in two different files, and two different folders. The first one is in folder src, and the second one in folder test (same project). Now imagine I have this code in my class1Test and function1ofClass1 is public:

class1 c1 = new class1();
    int a = function1ofClass1();
    int b = c1.function1ofClass1();

Obviously the first call of function1ofClass1 is not correct, but in this situation, why java (I am using eclipse) doesn't give me a compile error? I know that C# would. Am I doing something wrong with my filing organization or this is the way java works?

Answer 1

看来您的测试类扩展了包含该函数的类，这就是为什么编译器不给您编译错误的原因。

Answer 2

The first one is in folder src, and the second one in folder test

And you are using an IDE which has set this up for you. It has added src/java and test/java to your classpath: as such, classes class1 (in, say, src/java/foo/bar ) and class1Test (in test/java/foo/bar ) are in the same namespace.

It is therefore normal.

Answer 3

Is function1ofClass1 declared as static ? In that case both calls are perfectly valid, provided the function has been imported (which your IDE may have done for you).