I have been developing a binary search tree class using generics, and my class contains several Interfaces and inner classes, including a Tree node class, an interface for a callback (used by my iterators) an interface for a tree iterator, and several iterator classes that implement the tree iterator interface: Java Code: public abstract class BinaryTree implements Tree { BinaryTreeNode root; ... |
please have a look and see if you can help. question: You are required to create a class SolarSystem that will define an object containing a variable number of planets. You will put the definition for the class Planet inside the definition of the class SolarSystem. When a SolarSystem object is being created, the user specifies the name of the solar ... |
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I am studying to become a "Sun Certified Programmer", and would like to learn how to achieve multiple inheritance using inner classes. I "kind of" understand the technique, but need to solve a concrete problem. so, what should i do? Maybe, a group of comp. sci. professors has created a set of problems that they give to students and posted them ... |
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I want to access it from main method. public static void main(String args[]) { Anonymous a = new Anonymous(); a.pop(); } Here the output will be "Original pop". But how do i access the pop() method which is there in 'Sub' class so that the output is 'Anonymous pop' I think i had placed it more clearly now. |
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{code}public class MyOuter{ private int x = 7; public static void main(String[] args) { MyOuter outer = new MyOuter(); outer.outerFunc(); } public void outerFunc() { System.out.println("Printing Outer Variable from Outer: " + x); MyOuter.MyInner inner = new MyOuter().new MyInner(); inner.seeOuter(); MyOuter.MyInner.MyInner2 inner2 = new MyOuter().new MyInner().new MyInner2(); inner2.seeOuter2(); } }class MyInner{ private int x = 9; public void seeOuter() { System.out.println("Printing ... |
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Hello, I have started learning Java and I am really new to it. In reading the tutorials I found the subject of inner classes. To give it a place I thought of it as a spreadsheet: The spreadsheet is an outerclass while a column and a row are inner classes. Each class has its own typical fields and methods. On a ... |
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1. A question is not a doubt... check the dictionary. 2. There is no specific purpose for inner classes. They have the advantage of being able to access and mutate the private attributes of their outer class. Iterators and ActionListeners are commonly implemented as inner classes for exactly this reason. In fact ActionListeners are commonly implemented as anonymous inner classes, because ... |
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i know this creates an object of the Inner Class but i'm not sure how it does it. OuterC o = new OuterC(); 'o' is of type OuterC and then 'new OuterC()' calls the constructor and 'o' points to the object. but OuterC.InnerC i1 = o.new InnerC(); i'm not sure what's happening, can anyone help me try to understand it a ... |
I'm trying to make sense out of the need for an Inner Class; can variables be used instead of an Inner class? what functionality does the inner class offer that an instance variable/class methods cannot offer? Please refer to code fragment below when you respond? thanks. class Animal{ //why not String brainCharacteristics; instead of class Brain{ //code }//end inner class }//end ... |
Hello everyone. I just want to ask bout this inner class thing. Is it allright to make an inner classes more than one, let's said bout twenty of it? And how much is the limit size of a java class that u can make? Because i'm afraid that my class can be too large because it have a lot of inner ... |
Hi, I got myself a bit confused when I came across inner and derived classes. However, I know that the syntax for both are different. For inner classes: class OuterClass { ... class NestedClass { ... } } For inheritance: class ClassA { ... } class ClassB extends ClassA { ... } But I justed wanted to clarify if there's differences ... |
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i came across this code n I'm not able to understand how the code works how n when does all the functions get called i know that whenever the button is pressed an ActionEvent is generated n then the actionPerformed function is executed but when would the run fuction be executed in the above code at the time the control enters ... |
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Hi, I understand that inner classes have an additional privilege of having access even to the private variables and methods of a class. Apart from this, why would anyone want to use an inner class in their program? I did read explanations pertaining to scenarios where inner classes have been used to form "animations", but I still am struggling to understand ... |
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Hi I joined as a faculty last week in an institution. To take class I need some information about inner classes in java. Basically i need where we use this concept in real time application. Now it is used by the developer or not? Moreover how it is working in java? Please somebody help me out... thanks in advance Chithrakumar |
And your way is not possible , when I got Mother.java like this Mother.java [code] public class A { } class B { } [code] When I compile it , it becomes A.class and B.class , whick class object should I get ? If A.class include a inner class, may be I can check it out , but in this case ... |
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You didn't make life any easier by not supplying the text of the compilation error, but it's fairly clear: Test.java:34: Method(int) in inner.Outer cannot be applied to () Because inner.Outer extends Outer, the declaration of Method() with no arguments in Outer hides the declaration of Method() with one argument in the class Test, which is semantically more remote. You might be ... |
If it's non-static, it's more dependent on the enclosing class. Do you wish to use the inner class without an existing instance of the outer class? If yes, make it static. If you want the inner class instance to always be associated with an instance of the outer class, make it non static. |
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hiii i want to know something about innerclass. if we have inner class in a method the innerclass instanse does not refer to the method variable. it is because the local variable is on stack and inner class instance is on heap. And when method complete the stack is destroyed but we can refer the inner class somewhere else and store ... |
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Well I don't know what happened. I have been reading round this for over an hour before my original post and I couldn't get it to work. However, it does now. Thanks endasil for your response anyway. Thinking about it I expect I corrected the problem when cleaning up my code to post here! |
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Mrjavan wrote: What the purpose and use of java Inner class ? A class defined within another class is called Nested Class. Non-static nested classes are called inner classes. For a good example of inner class, you can see LinkedList.ListItr which is a private inner class. Its purpose is to provide an implementation of ListIterator for a LinkedList. It would be ... |
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The Inner2 constructor is trying to call Inner1's default constructor. Since Inner1 is an inner class, you need an instance of it's outer class to create an instance of Inner1. The outer class instance used is the currently executing instance of Outer (Outer.this). We have to say Outer.this because if we just call super() (or this.super()) the currennt instance will be ... |
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Not really. It's not something that can be briefly summed up satisfactorily. You'd only have loads more questions. Your best bet is to Google for a description of them, you'll get all the information in one clear, consise lump then, and won't have to wait for replies to the questions you're bound to have. If you still don't understand them after ... |
One of the biggest mistakes I see people make when programming with XML, is to stick to one method all the time. A typical scenario is that they'll use , for example, JDOM, think "Oh, that's really easy!" and use it all the time not realising that the complexity of the code for moving between XML and Java objects using JDOM ... |
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i am designing a GUI based program that needs to have 2+ windows that interact with each other. In my original design there were just two windows: the World display, and the tile choser (this is for 2D map editing). Because there were only 2, I made them both inner classes of another class. The top level class's fields were how ... |
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As you may know there's a rule in OO saying "prefer composition over inheritance". The inner class mechanism of Java can be used to implement composition. From a design perspective the inner classes will be related by proxy rather than inheritance, and they will be able to share implementation available in the outer class via composition rather than inheritance. |
So in this case, even when I would use variable k inside the constructor, k would be already initialized, as the static initialization occurs from top to bottom. The only requirement would be when compiler generates a class for an enum, it would have to make sure that enum fields are initialized as the last ones as it is in the ... |
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Here the outer class reference of the newly constructed TimePrinter object is set to this reference of the method that creates the inner class object. the this. qualifier is redundant. However, it is also possible to set the outer class reference to another object by explicilty naming it. For e.g if TimePrinter were a public inner class, you could construct a ... |
What sort of response are you expecting here? Do you want to know the internals of the JVM? Anyway here is my advice after browsing some of your posts. Don't start learning Java by reading a certification book. That book tells you that as well. Better start by reading the Sun(Oracle) tutorial to understand all the basic concepts first. That way ... |
Hi All, I Have a class that as an inner class. I know that the inner class has access to all the fields and methods of the outer class but what I can not find is any info about what access does the outer class as to the fields of the inner class. I have a method of the outer class ... |
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Hi, I'm wondering if it's possible to make an inner class (defined inside a function) into a singleton, so let's say I define a class inside a member function then somewhere inside that function I instantiate that class but I only want that class initialized once no matter how many times that function is called. The only solution I've come up ... |
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That's actually pretty clear. You have a public interface and a public outer class. The outer class has an inner class marked as private which implements the interface. It also has a method that is defined as returning something that implements the interface, which you will satisfy by returning an instance of the inner class. You have to show that the ... |
I wrote the following piece of code: package pack1; class one{ private int f1; private void pvm() { System.out.println("pvm"); } class innerone { public void mod() { one.this.f1=5; one.this.pvm(); } } public void callin() { innerone i= new innerone(); i.mod(); } } /** * * @author Arkid */ public class C72 { one o= new one(); o.callin();// ***Code fails here*** } ... |
class A { }; class B { }; public class C { } so when I compile class C it generate three class files A.class,B.class,C.class because class A & B are not inner classes It does not create class name with $ so please tell me how to access this class names also. Thanks, Manesh |
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This thing runs fine when executed inside my RAD workspace. However, I created an exact replica outside the workspace so I can run it from the windows command line. When I try to do that, I get an exception associated with the code within the try statement ( fileParser = parser.loadConfigurationFile(MAPPING_FILE_NAME); ) inside the inner class (PCFIfile). The important point is ... |
A VerifyError means that the class you are trying to load has some internal errors or security problems (as the JavaDoc says). The reason you get it in 1.5 and not in 1.4 is probably because the checks for those errors got stricter in 1.5. You'll need to get a correct version of that class (if you've got the source, try ... |
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Poonam_Agarwal wrote: is ActionListerner() is a interface. Yes, you can base an anonymous class either on a class or an interface. is this example is related to Adapder classes?? Kind of, though Addapters are only useful where the listener has more than one method defined. An addapter is simply a class which implements and interface with no-op methods. By extending an ... |
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hi i am having a problem with a couple of variables. C:\a1\player1>javac *java SimpleTableDemo.java:89: local variable p is accessed from within inner class; n eeds to be declared final man.removeLoggedIn(p); ^ SimpleTableDemo.java:89: local variable man is accessed from within inner class; needs to be declared final man.removeLoggedIn(p); ^ why does this happen? thanks. |
Hi I was wondering if it is possible to have an inner class that is implemented in a certain way depending on certain parameters. For instance, the class I am making has 2 fields. I want the compareTo method to compare to the 1st or 2nd field depending on parameters from the method that creates the inner class. I add this ... |
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$ javac -Xlint:unchecked -d "$HOME/project/smis/bmlaytest/classes" -cp "." decode_ATPSSIS075.java decode_ATPSSIS075.java:106: warning: [unchecked] unchecked call to put(K,V) as a member of the raw type java.util.Map map.put(fieldNames, new Integer(i)); ^ decode_ATPSSIS075.java:159: warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.List ((List)this.fields.get(nvp.name)).add(nvp.value); ^ decode_ATPSSIS075.java:162: warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.List values.add(nvp.value); ^ ... |
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okay... let's give this a go how many OuterTest objects are there? there's the one that you instantiate with "STP", and the one that is created as base class as you instantiate InnerTest. so, looking at it from your (one) InnerTest instance, there's an enclosing OuterTest (the first one) and a base OuterTest (the second one). so how many OuterTest.id's are ... |
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AAMAF, the entire innter class only exists if an object of the outer class exists. This implies that so called static members/methods could only exist if an object of the outer class exists (see above). That wouldn't be really static would it? Note however that an object from an inner class can access the static members and methods from the outer ... |
It's an inner class that you simultaneously define and instantiate, without giving it a name. You don't need to name it if you instantiate it the same time as you define it. An inner class is a nested class that has an implicit reference to its surrounding class. A nested class is a class defined inside another class. They're useful, because ... |
class option{ int x,y; int number1 = Kalkulator1.this.number1; int number2 = Kalkulator1.this.number2; void pilihan(int x) { if (x == 1) {System.out.println("Operasi yang digunakan adalah Penjumlahan"); int y = (number1+number2); System.out.println("Hasil dari operasi adalah = " + y);} else {if (x == 2) {System.out.println("Operasi yang digunakan adalah Pengurangan"); int y = (number1-number2); System.out.println("Hasil dari operasi adalah = " + y);} else {if ... |
am in a static method. my innerclass is a member class as in it's created within the blocks of the class not within blocks of a method. i would like to create an object of this member class. the code i should type if i were in a statid method is outer.inner i = new outer().new inner(); now my books says ... |
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# ls ColorChooserEditor*.* ColorChooserEditor$1.class ColorChooserEditor.java ColorChooserEditor.class // file 1 ColorChooserEditor.java import java.awt.BorderLayout; import java.awt.Color; import java.awt.Component; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.table.*; public class ColorChooserEditor extends AbstractCellEditor implements TableCellEditor { private JButton delegate = new JButton(); Color savedColor; public ColorChooserEditor() { ActionListener actionListener = new ActionListener() { public void actionPerformed(ActionEvent actionEvent) { Color color = JColorChooser.showDialog(delegate, "Color Chooser", savedColor); ... |
Hi, I've a little problem: I want to create bonus objects for my game, all bonus can appears casually during the time of game, so they can be visibles or not visibles. If I pick a "bonus cherry", one life is give to the player If i pick a "flower bonus", invincibility is give to the player etc etc.. So, how ... |
Thanks Cotton, I actually went to that site and it didn't look like it told you how to access an outer object from an inner class. Maybe I missed something, I have a feeling this has an easy solution, even though I'm accessing the ArrayList from a method in the inner class. |
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Using a static nested class can be compared to using a static field or a static method, in this context. For any static field/method, within the class we can just refer the static filed or call the static method, without the need to mention the class name. Whereas when used from other classes, we use CLASS_NAME.FIELD / CLASS_NAME.METHOD. Same holds good ... |