来自内部类的Java方法调用与外部类的输出不同

public class OuterClass {
    private int outerVariable = 10;

    public void outerMethod() {
        InnerClass inner = new InnerClass();
        inner.innerMethod();
    }

    public class InnerClass {
        public void innerMethod() {
            System.out.println("内部类方法调用：outerVariable = " + outerVariable);
        }
    }
}

public class Main {
    public static void main(String[] args) {
        OuterClass outer = new OuterClass();
        outer.outerMethod();
    }
}

内部类方法调用：outerVariable = 10