This is not possible, since everything you define in a class becomes a valid member only in an instance of that class, unless you define a method with @staticmethod, but there is no such property for a class. So, this won’t work either: class Foo(object): x = 10 class A(object): pass class B(object): other = … Read more
The method getValue() and the field value are both private. As such, they are not accessible to any other classes, including sub-classes, ie. they are not inherited. In InnerClass#showValue() public void showValue() { System.out.println(getValue()); System.out.println(value); } because of the fact that those are private, getValue() and value are referring to the outer class’ members, which … Read more
The latter is more explicit and will allow you to call the outer class method if one exists in the inner class with the same name. class OuterClass { void foo() { System.out.println(“Outer foo”); } View.OnClickListener mListener1 = new View.OnClickListener() { void foo() { System.out.println(“Inner foo”); } @Override public void onClick(View view) { foo(); //Calls … Read more
Yes, that’s fine. From the JLS, section 6.6.1: Otherwise, if the member or constructor is declared private, then access is permitted if and only if it occurs within the body of the top level class (ยง7.6) that encloses the declaration of the member or constructor. You can even refer to a private member of nested … Read more
Sometimes there is some functionality which is best represented as an object, but which is only meaningful within the context of another object, which does not necessarily need to be exposed to the outside world, and which can benefit from having access to the parent classes data (so as to not violate encapsulation). The best … Read more
Assuming your outer class is called Outer, from the scope of the inner class(non-static), Outer.this.foo to get at the field. For example, Outer.this.foo=new ArrayList<>(); where Outer is the name of the class and foo identifies the field. You can also grab it directly as foo=new Baz() but it’ll pick the inner field if there’s a … Read more
Inner classes are best for the purpose of logically grouping classes that are used in one-place. For example, if you want to create class which is used by ONLY enclosing class, then it doesn’t make sense to create a separate file for that. Instead you can add it as “inner class” As per java tutorial: … Read more
You should annontate your class with @RunWith(Enclosed.class), and like others said, declare the inner classes as static: @RunWith(Enclosed.class) public class DogTests { public static class BarkTests { @Test public void quietBark_IsAtLeastAudible() { } @Test public void loudBark_ScaresAveragePerson() { } } public static class EatTests { @Test public void normalFood_IsEaten() { } @Test public void badFood_ThrowsFit() … Read more
In my view, 90% of inner classes in Java code are either entities that are associated with a single class and were thus “shoved in” as inner classes, or anonymous inner classes that exist because Java does not support Lambdas. I personally don’t like seeing complex inner classes. They add complexity to the source file, … Read more
Intro: Nested classes relate to other classes a little differently than outer classes. Taking Java as an example: Non-static nested classes have access to other members of the enclosing class, even if they are declared private. Also, non-static nested classes require an instance of the parent class to be instantiated. OuterClass outerObj = new OuterClass(arguments); … Read more