I keep running into the 'cannot find symbol' error on my class. The variable is clearly declared in the super class, yet the subclass can not see it. I ... |
I have JSON like the following:
[{
'kind':'1',
'value1': 'foo',
'value2': 'bar',
...
},
{
'kind':'2',
'value1': 'foo',
'value2': 'bar',
...
}
..]
Basically a list of objects with ... |
I am writing an abstract class and I have a variable that should be defined by the sub-class (in this case it is an int which is used in the super-class). ... |
- Can a subclass variable be cast to any of its superclasses?
- Can a superclass variable be assigned any subclass variable?
- Can a superclass be assigned any variable?
- If so, can an interface ...
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In the code below, myString is always initialized to null. I have to manually initialize in an init() or similar. As far as I can tell it is related to superclass/subclass ... |
This is probably answered somewhere, but I have no idea what to search for. Imagine you have the following...
The superclass, Animal.java
public class Animal {
public String noise = "squeak";
...
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I have four classes. Class Person, and three more, Student, Professor, Tutor, each of which extends class Person. Class Person has 2 variables studentID and staffID. However, only student can have ... |
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class A {} class B extends A {B b = new B(); A a = new A(); A a = b; } As the above classes give an example of superclass type variable containing a reference to a subclass object. I read that subclass objects can be treated as superclass objects.And that a superclass type variable that contains a reference to ... |
I understand how to call superclass variables from a subclass. But what if I wanted to call subclass variables from the superclass. Or even sub subclass variables (a subclass inside a subclass of the superclass) from a superclass. I want to reach down the Hierarchy for variables as opposed to reaching up (like when using super). How do I do that? ... |
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I am going to go out on a limb and assume this is related to your other thread from earlier today. This is one of those instances where recursion can be your friend. I whipped up the following example using your LinkedStackClass code in your other thread. (It's runnable but I had to slightly alter it to account for your other ... |
I have created a Class (Class 1). And from that Class, I created 3 other Subclasses (Subclasses 1,2, and 3). Now, I have a Vector of type Class 1. Each subclass has a specific field that is know as its "selected item", as in it it the currently display selection on the screen. (It would be from a JCheckBox, JSpinner, or ... |
Hi, jverd wrote: It should be covered in the JLS [http://java.sun.com/docs/books/jls/third_edition/html/j3TOC.html] I've not been able to find any mention of this behavior in the spec, although I may not have looked close enough. jverd wrote: If the only difference between those classes is the static init blocks and you're always only invoking a non-hidden static method in the parent, I'd say ... |
class Dog also has a variable called "name". Dog is extending Animal class and hence the "name" variable is overridden. When u create an object for class Dog like, Dog d = new Dog(); or Animal a = new Dog(); //remember in both cases its an object of Dog only the variable in class Dog gets initialized and hence it will ... |
When you refer to an instance method, like display(), which class' version of that method is invoked gets determined at compile time, and it's based on the type of the actual class--the runtime type. This is Java's runtime polymorphism. The only members that are polymorphic this way are those that meet all of the folowing criteria: * They are instance (non-static) ... |