Linkage Class / Base Class conflict?

I'm trying to create Flash components for Flex. Part of that
is linking the library entry for a movie clip to the class
definition of it. In this case, it's a simple blue square that I'm
trying to link to view.BlueSquare which extends
mx.core.UIMovieClip. It finds the class successfully, but I am
unable to close the dialog box because I get an alert warning me
that the base class will not be used as I click the OK button. The
only way I am able to close the dialog box is if I do not enter the
name of an existing class file in the "Class" field. This is very
frustrating... what am I doing wrong?

io.class is an obfuscated class and some of the Eclipse tools don't work well with them. For example, using control-shift-T to see the list of classes won't find com.businessobjects.lang.cal.compiler.io nor com.businessobjects.lang.cal.compiler.ip for that matter, but you can browse to these classes in the package explorer and see them in the calPlatform.jar. However, any api class (as documented in our public Javadoc) should be accessible. Does this answer your question, or do you have a more specific problem? Reproduction steps in Eclipse would work best for us since that's what we're using. <p> Bo </p>

Similar Messages

Cannot find Super class/Base class when extending VO

I am extending a SQL based VO and when I select the extends in the VO Wizard step 7. I am unable to find the base class for the object and rowimpl. I have copied them in the class path and still they don't show up (but can see other classes) ? Could you please tell where am I going wrong?
Thanks,
Hari

Well here is the deal - I have the whole of $JAVA_TOP/per directory in my class path and also under myprojects/oracle/apps/per directory. I have created a BC4J abc.oracle.apps.per.selfservice.appraisals.finalrate. Here is where I will be creating the new SQLVO. In the step 7 of VO Wizard there is extends button when I select and navigate through oracle.apps.per.selfservice.appraisals.server I don't see my FinalCompListVORowImpl class although I could see it in the navigator. Do I need to navigate to this level for step7 of VO Wizard or default it to oracle.jbo.server.ViewRowImpl? Also I have included the Java and xml files in my project. Your help is appreciated.
Thanks,
Hari

Export for AS: Class vs Base Class

when i export a movie clip for actionscript, what are the differences between Class & Base Class? i see most tutorials change Base Class and leave Class as the name of the movie clip defined in the library.

the main use of the base class is to extend it so many different classes can share it's functionality.
but even when not needed as a super class, the base class is also helpful when you want to instantiate many different objects using code and you don't want to write/compile many different class files.
if flash finds you failed to write a class file (for every class exported for actionscript), flash writes a default class files for you.

How to use reflection to get base classes protected field

I have one base Base classes which have protected fields and public get method to get the field.
class Base
protected int proField;
public int getProField(){return proField;}
Class Derive extends base class Base
class Derive extends Base implements OtherInterface
public void funtion(){};
Now I have an instance of Derive, how can I use reflection to get the protected field inherited from Base. It seems Java Reflection only give runtime accessibility to public field and decleared field, protected-inherited field is excluded.
Thanks
Lei

as the last poster said, traverse up the class hierarchy.
ex:
private void doSumfinToField(String fieldName throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException {
Class clazz = getClass();
Field field = findFieldInClass(clazz, fieldName);
//field.doSumfin;
private Field findFieldInClass(Class clazz, String fieldName) throws NoSuchFieldException {
try { // to find the field in this class
return clazz.getDeclaredField(fieldName);
} catch (NoSuchFieldException e) {
// if we don't have a superclass, continue
if (clazz.getSuperclass().equals(Object.class)) {
throw e;
// check in the superclass
return findFieldInClass(clazz.getSuperclass(), fieldName);
}

Symbols + Base-Class Workflow

I frequently create a lot of Library Symbols, export for Actionscript, letting Flash auto-generate the Class & extending a custom base-class in order to give them all custom functionality w/out having to create a Class for each, and/or without having to create a FactoryClass for instantiating X number of ClassObjects for each Symbol to be added to.
It's really fast for prototyping, and with this workflow I've only hit a few obstacles. Those are:
1 - If the Symbol has children you cannot give the children instance-names, else the compiler gives an error related to automatically declaring stage instances. Two workarounds for this are that you can uncheck automatically declare stage instances, and do it manually in your base-class. or you can avoid using instance-names, and use getChildAt().
2 - If the Symbol is a MovieClip, the timeline doesn't inherit the base-classes imports. I don't have a workaround for this.
My question is, are these limitations that could be addressed by Adobe's Flash team, or are they limitations that are unavoidable without altering the workflow?

Vote for this idea at ideas.adobe.com Flash Professional: http://tinyurl.com/2bxew2x
Problem Description:
Using the Library to export Symbols for Actionscript hits a severe wall when Symbols use auto-generated classes + base-classes. Child instances are declared as their auto-generated class type instead of their base-class. The result is that you cannot create 2 Library Symbols with auto-generated classes which inherit from a user-defined base-class which have named child instances with auto-generated classes & a user-defined base-class.
Steps to Reproduce:
1.     Create 2 Library Symbols, export for Actionscript with base-class "Character" which extends Sprite. Let Flash auto-generate Class names "Character1" & "Character2".
2.     Create 2 more Library Symbols, export for Actionscript with base-class "Head" which extends Sprite. Let Flash auto-generate Class names "Character1Head" & "Character2Head".
3.     Place an instance of Character1 on the stage, and give it a child instance of "Character1Head" named "head".
4.     Place an instance of Character2 on the stage, and give it a child instance of "Character2Head" named "head".
5.     Test Movie or Publish
Actual Result:
Warning: All instances named 'head' will be automatically declared as "Character1Head" in symbols that use "Character" as their base class. In symbols that are linked to user-defined base classes, instances with the same name must be of the same type.
Expected Result:
Flash should declare all instances named "head" as their base-class type "Head" when using auto-generated Classes. Save this workflow!!!

Base Class vs Class in the linkage panel

I have 2 dozen movie clips in the libarary that are all the same structure, but with different content, and I wanted to write a single class that would work for all of them. Popping this in as the base class worked great until I wanted to pass in some arguments to the constructor. Suddenly, it seems I have to write a "shell" class for each asset that contains nothing but super(arg1,arg2) in its constructor (all 24 of them - ugh!). This ends up being really clunky. Is there any way around it?
Also - in discussing this with a colleague, an issue came up about the exact relationship between the items in the Class and Base Class fields in the linakge panel for a library asset. What exactly is therelationship? Does the class always extend the base class, or is there something else going on?

undo whatever you did that caused that problem. you probably assigned a class name that matched one of your base classes.

Extending class + accessing base class's children

Hello.
I'm trying to create a sort of info and tool panels for a project, similar to the ones on the Adobe Suite's products. They'll have a tab that you can double click to open or close them and the panel's title will be on this tab.
So I created a MovieClip called MainPanel and inside it I placed a textfield called txtTitle and a rectangular MovieClip called mTab. I duplicated the MainPanel twice on the stage, called them PanelA and PanelB, and added individual elements to them, but kept the txtTitle and mTab. I edited PanelA and PanelB's linkage options to link them to specific custom classes.
First I created a base class for the MainPanel.
package com.panels{
    import flash.display.MovieClip;
    import flash.events.MouseEvent;
    import fl.text.TLFTextField;
    public class MyPanel extends MovieClip {
        public function MyPanel ():void {
            txtTitle.mouseEnabled = false;
            mTab.doubleClickEnabled = true;
            mTab.addEventListener(MouseEvent.DOUBLE_CLICK, clickedPanel);
And then the classes for Panel A and B, which extend the MainPanel.
package com.panels{
    import com.panels.MyPanel;
    public class PanelA extends MyPanel {
        public function PanelA ():void {
When I test the movie, I get an error saying "Access of undefined property txtTitle" (and the same for mTab). If I just link PanelA to the MainPanel class it all works - I got it to open, close, dragged it with the mouse... I can access mTab, txtTitle and anything else already on the stage. But if I extend the class, I no longer can. Does anyone know why this happens and the best way to get it to work? Thank you.

Still didn't do the trick, I even tried building a project from scratch with just the classes I mentioned in my example and nothing else, and then a second version where I have all files on the same directory. Not sure if it might have something to do with this being for an AIR app.
I have found a solution that seems to be working. My new MyPanel class:
package com.panels{
    import flash.display.MovieClip;
    import flash.events.MouseEvent;
    import fl.text.TLFTextField;
    public class MyPanel extends MovieClip {
        private var _title:TLFTextField;
        private var _tab:MovieClip;
        public function MyPanel ():void {
            _title = MovieClip(getChildByName("txtTitle")); //If I don't cast the result as a MovieClip I get an error
            _tab = TLFTextField(getChildByName("mTab")); //Same for the TLFTextField
            _title.mouseEnabled = false;
            _tab.doubleClickEnabled = true;
            _tab.addEventListener(MouseEvent.DOUBLE_CLICK, clickedPanel);
Still I'd like to understand why I need to go through these hoops so I don't make the same mistake again.

AS3: How to create one base class for classes loaded in multiple swfs?

Our application have 3 different modules and all use
fscommand and ExternalInterface alot. Now the problem is we are
combining all those modules, but they all will reside in different
swfs. Is there any way that they extend to same base class and its
static members have only one instance accessible by all
three?

Hi,
You can achieve this via Workshop 9.2 by using the exported Ant script for your project as follows:
-Ensure that all Jars needed to resolve com.bea.p13n.property.EntityPropertyManager (this particular class is found in weblogic92/common/p13n/lib/p13n_ejb.jar) and all referenced classes are added to the Java build path for your WebLogic EJB project (Properties->Java Build Path->Libraries)
-Export the "Workshop Ant Script" for your WebLogic EJB project (File->Export->Workshop Ant Script); this will generate a "build.xml" Ant script under your project root directory.
-Edit this default build script as follows: in the call to the "ejbgen" task within the "build" target, add the attribute: propertyFile="ejbgen.properties"
-Create a file "ejbgen.properties" under the root of your WebLogic EJB project and add the following entry:
YourSessionBeanClassName.remote.baseClass=com.bea.p13n.property.EntityPropertyManager
-Add a "<path refid="java.classpath"/>" within the "<classpath>" for the "java" task element that calls "weblogic.ejbc" (this will ensure that the p13n classes are resolved by EJBC)
Follow the instructions for executing the Ant build script found here: http://edocs.bea.com/workshop/docs92/ws_platform/ideuserguide/conUseCustomAntBuild.html
For more information on the EJBGen property file support, see: http://e-docs.bea.com/wls/docs92/ejb/EJBGen_reference.html

Warning :: Derived class hides the base class virtual function

We are porting from CC5.3 to CC5.8 compiler with Sun Studio one compiler. After plenty of hurdles we are in the final stage of removing the warning messages... Amoung the plenty the following one is very common and in different files. Why am I getting this error in 5.8 and not in 5.3 compiler....
Warning: derived_Object::markRead Hides the virtual function base_Object::markRead(ut_SourceCodeLocation&) const in a virtual base
From this it is easily understandable that the base class mark read was hidden by derived class markRead... when we drive and override the derived class function.... It is all over the place....
Thank you,
Saravanan Kannan
//public: using xx_Object :: markRead;
virtual void markRead() const;

The Sun C++ FAQ discusses the warning message:
http://developers.sun.com/prodtech/cc/documentation/ss11/mr/READMEs/c++_faq.html#Coding1
Notice that warnings are not necessarily errors. But I applaud your desire to fix the code so that it generates no warnings. I wish more of our customers could be persuaded to do the same. :-)
C++ 5.3 issues this warning, by the way. Example:
struct B { virtual int foo(int); };
struct D : B { virtual int foo(double); }; // line 2
D d;
line 2: Warning: D::foo hides the virtual function B::foo(int).
If for your particular code you do not see a warning with C++ 5.3, it would be due to a bug in C++ 5.3 that was later fixed.

Class override, how to create the child class and then the base class

I started to write a program for a smart DMM, the problem is every version of the DMM the company change the communication commend.
My idea is to write a child class for every DMM version and every SubVI of the child will override the base class SubVI.
My problem is, i want first to create one child class and after i will see every thing is work, start to create the base class. that way i will see if am thinking the right way.
My question is
How can i create a child class and then create the base class and configure the SubVi of the child class to be Override of the base class?
I tried to search in the property of the class but i didn't see nothing.
Thanks
Solved!
Go to Solution.

This can be done and I've done it on occasion.
You simply create the base class with the dynamic dispatch methods you require (connector panes need to be identical to thos of the child class).
Then set the inheritance of the class to inherit from this base class. If your method is defined as a dynamic dispatch method in the parent, you'll most likely now have some errors (unless your child method was already DD in which case you might just be OK already).
To change the inheritance of a class, right-click the properties of the class in your project and select properties. I believe the ineritance tree is at the lower end of the properties. Click on the "change inheritance" (or something similar) to choose the class from which you now wish to inherit.
Say hello to my little friend.
RFC 2323 FHE-Compliant

How to specify a base class for Remote Interface in Workshop 9.2? -- URGENT

Hi,
I am trying to create a UUP EJB in WebLogic 9.2 workshop. I am using @FileGeneration to create my home & remote interfaces. And the generated remote interface is extending javax.ejb.EJBObject;I want my remote interface to extend com.bea.p13n.property.EntityPropertyManager which in turn implements javax.ejb.EJBObject. Can someone tell how i can do it in Workshop?.
I came across Predefined Variable: remote.baseClass and as per docume
ntation..."If specified, the value of this variable will be used as the base class for all generated remote classes. Where i should specify it?. @FileGeneration does nt have any option for it. Any help is grtly appreciated.
Following are my code snippets:
IMPL Class
@FileGeneration(remoteClass = Constants.Bool.TRUE,remoteHome = Constants.Bool.TRUE, localClass = Constants.Bool.FALSE, localHome = Constants.Bool.FALSE,remoteClassName = "MyEntityPropertyManager",remoteHomeName = "MyEntityPropertyManagerHome")
public class MyEntityPropertyManagerImpl extends GenericSessionBean implements
SessionBean {
//code
}

This question was posted to both the bea.workshop.developer.general and weblogic.developer.interest.workshop (I had replied to the later on 10/19); after seeing an identical question today on this list want to include a reference to that reply here:
http://forums.bea.com/bea/message.jspa?messageID=600044925&tstart=0
-Rob

How to expose and code the event handlers of a base class?

I have created a class that inherits NumericUpDown. When I instantiate an object from that class, I can make it visible and have it appear on my form just like any other NUD. How can I get that instantiated object to expose the event handlers of its base
class, the NUD in this case, so that, for example, I can tell the client what action to take when the value of the instantiated object changes?
Thanks for your help.

I am not sure exactly what you mean. Are you adding your NUD controls to the Form at design time from the toolbox or adding them in code at run time? If you are adding them to the form from the toolbox then you access the events the same way
you would a standart NUD control. If it is at runtime and you have a fixed amount of them you are going to add then you can declare them Class Scoped using the
WithEvents keyword which will let you access all their events.
Public Class Form1
Private WithEvents Nud1 As New NUD
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.Controls.Add(Nud1)
End Sub
Private Sub Nud1_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Nud1.ValueChanged
Me.Text = Nud1.Value.ToString
End Sub
End Class
Public Class NUD
Inherits NumericUpDown
'Your custom code to make it work how you want...
End Class
If this is not what you are doing then you may need to explain a bit more and show the code you are using so we understand better.
If you say it can`t be done then i`ll try it

Error with instance variable and constructor of base class

I am getting the error on the following statement "protected Point apoint" of by base class. What is causing this problem? See my code:
package Shapes;
public abstract class Shapes
     protected Point apoint; / ****error at this line****/
     public void move(double xdelta, double ydelta)
          apoint.x += xdelta;
          apoint.y += ydelta;
public abstract void distance();
public abstract void show();
public String toString()
return "\nThe starting point is at coordinates ("+x+","+y+")";
package Shapes;
public class Lines extends Shapes
protected Point start;
protected Point end;
     protected double x;
     protected double y;
     double delta;
     public Lines( final Point apoint, final Point bpoint)
start.x = apoint.x;
          start.y = apoint.y;
          end.x = bpoint.x;
          end.y = bpoint.y;
public Lines(double xstart, double ystart, double xend, double yend)
this.xstart = xstart;
          this.ystart = ystart;
          this.xend = xend;
          this.yend = yend;
     public Lines(double x, double y)
          this.x = x;
          this.y = y;
               public void distance(final Lines start, final Lines end)
                    delta = abs(Math.sqrt (super.x - start.x) * (super.x - end.x) +
                    (super.y - start.y) * (super.y - end.y));
               Lines move(Point start, double delta)
                    end.x += delta;
                    end.y += delta;
                    return new Point(end);
public Lines show()
g.drawLine( start.x, start.y, end.x, end.y);
public String toString()
return super.toString()+ "\n moved distance is("
               + start + ") : (" + end + ")"
               +" \n to position(" + start + " ) : (" + end + ")";
package Shapes;
public class Rectangle extends Lines
     double delta;
public Rectangle (Point top_lft_pt, Point bottom_rght_pt)
super(top_lft_pt, bottom_rght_pt);
public Rectangle(double x_top_lft, double y_top_lft, double x_bottom_rght, double y_bottom_rght)
super(x_top_lft, y_top_lft, x_bottom_rght, y_bottom_rght);
     public Rectantgle is_it_diagonal()
          if(top_lft.x > bottom_rght.x && bottom_rght.x < top_lft.x)
               System.out.println("Point are Not Diagonal");
               public void distance(double delta)
                    delta = abs(Math.sqrt (top_lft.x - bottom_rght.x) * (top_lft.x - botton_rght.x) +
                    (top_lft.y - bottom_rght.y) * (top_lft.y - bottom_rght.y));
               public Rectangle move(final Point top_lft_pt, double delta)
                    bottom_rght.x += delta;
                    bottom_rght.y += delta;
                    return new Point(bottom_rght_pt);
               public void get_top_rght_coords()
                    Point top_rght = new Point();
                    top_rght.x = bottom_rght.x;
                    top_rght.y = top_lft.y;
               public void get_bottom_left_coords()
                    Point bottom_lft = new Point();
                    bottom_lft.x = top_lft.x;
                    bottom_lft.y = bottom_rght.y;
     public Rectangle show()
                    g.drawLine(top_lft.x, top_lft.y, top_rght_x, top_rght_y);
                    g.drawLine(bottom_lft.x, bottom_lft.y, bottom_rght.x, bottom_rght.y);
                    g.drawLine(top_lft.x, top_lft.y, bottom_lft.x, bottom_lft.y);
                    g.drawLine(top_rght.x, top_rght.y, bottom_rght.x, bottom_rght.y);
package Shapes;
public class Circles extends Lines
protected double radius;
     public double delta;
     protected Point center;
public Circles(double x, double y, double radians)
super(x, y);
          radius = radians;
     public Circles(Point acenter)
          center.x = acenter.x;
          center.y = acenter.y;
public void distance()
delta = abs(Math.sqrt(super.x - x) * (super.x - x) + (super.y - y) * (super.y -y));
     public Circles move(final Point Circles, double delta)
          return new Point(Circles);
public void show()
g.drawOval(Circles.x, Circles.y, radius, radius);
package Shapes;
import java .math .*;
import java.util .Random ;
public class ShapesDriver
Shapes[] aShape = new Shapes[10];
static double range = 101.0;
static Random r1 = new Random();
public static void main(String [] args)
double[][] coords = new double[10][10];
double[] radians = new double [10];
Shapes anyShape = {
new Circles(radians),
new Lines(coords),
new Rectangle(coords)
Shapes aShape; /***error at this line***/
          for(int i = 1; i <= coords.length; i++)
for(int j = 1; j <= coords.length; j++)
                                                  coords[i][j] = r1.nextDouble () * range;
                                                  radians[j] = r1.nextDouble () * range;
aShape[i] = anyShape[r1.nextInt(aShape.length)];
System.exit(1);

Thanks for your help with this problem. Now I have another problem that I am having a hard time figuring out. My program is using inheritance and polymorphism. I trying to use only one version of methods in the superclass points which extends the shapes class which is the abstract superclass vs. repeating the implementation of the methods (move, show, etc.) in each of the subclasses. The error I am getting is this "declare the class abstract, or implement abstract member 'Point Shapes.move()'. As you see, move is declared abstract and of type point in the Shapes superclass and it's behavior is implemented in the subclass Points extending Shapes. The other subclasses, circle, rectangle and lines will invoke the move method from Points and return a new point object. Why I am I getting the error to declare or implement move when the implementation is in Point?
Below is code, please help?
import java .awt .Point ;
public class ShapesDriver
     public static void main(String args[])
          int count = 0;
          int choice;
          Point start = null;
          Point end = null;
          System.out .println(" 1 i am here");
          start = new Point((int)(Math.random()* 10.0), (int)(Math.random()* 10.0));
          end = new Point((int)(Math.random()* 10.0), (int)(Math.random()* 10.0));
     System.out .println(" 2 i am here");
     System.out.println (start);
     System.out.println(end);
     for(int i = 0; i <= count; i++)
          System.out .println(" 3 i am here");
          choice = (int)(4.0 * Math.random());
          System.out .println(" 4 i am here");
          System.out.println (choice);
     switch(choice)
          case 0: //Lines
          System.out .println(" 5 i am here");
          Lines apoint = new Lines((int)(Math.random()* 10.0), (int)(Math.random()* 10.0),
                              (int)(Math.random()* 10.0), (int)(Math.random()* 10.0));
          Point coords = new Point((int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0));
          new Point((int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0));
          break;
          case 1: //Circles
          System.out .println(" 6 i am here");
          Circles center = new Circles((double)(Math.random()* 10.0),
          (double)(Math.random()* 10.0), (double)(Math.random()* 10.0),
          (double)(Math.random()* 10.0),(double)(Math.random()* 10.0));
          Circles centerpt = new Circles((int)(Math.random()* 10.0),
          (int)(Math.random()* 10.0), (int)(Math.random()* 10.0),
          (int)(Math.random()* 10.0), (double)(Math.random()* 10.0));
     break;
          case 2: //Rectangles
     System.out .println(" 7 i am here");
          Rectangle top_lft_pt = new Rectangle ((double)(Math.random()* 10.0),
                         (double)(Math.random()* 10.0), (double)(Math.random()* 10.0),
                         (double)(Math.random()* 10.0), (double)(Math.random()* 10.0),
                         (double)(Math.random()* 10.0));
          Rectangle bottom_rgt_pt = new Rectangle ((double)(Math.random()* 10.0),
               (double)(Math.random()* 10.0), (int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0), (int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0));
     break;
     default:
     System.out .println(" 9 i am here");
     System.out.println("\nInvalid shape choice =" + choice);
     System.exit(0);
     break;
     try
               System.in.read();
               catch(java.io.IOException ioe)
import java .awt .Point ;
public abstract class Shapes
     private String shape;
     public Shapes(String ashape)
          shape = new String(ashape);
     public abstract Point move();
     public double distance()
          return 0.0;
     public abstract void show();
     public String toString()
          return "\nThis shape is a" + shape;
import java .awt .Point ;
public class Rectangle extends Points
     protected Point top_lft;
     protected Point top_rgt;
     protected Point bottom_lft;
     protected double top_lft_x;
     protected double top_lft_y;
     protected double bottom_rgt_x;
     protected double bottom_rgt_y;
     protected Point bottom_rgt;
     protected double delta = 0;
     protected String shape = "Rectangle";
     public Rectangle(double x, double y, double top_lft_x,
                         double top_lft_y, double bottom_rgt_x,
                         double bottom_rgt_y)
          super(x, y);
          top_lft_x = top_lft_x;
          top_lft_y = top_lft_y;
          bottom_rgt_x = bottom_rgt_x;
          bottom_rgt_y = bottom_rgt_y;
     public Rectangle( double x, double y, Point bottom_rgt, Point top_lft)
          super(x, y);
          bottom_rgt_x = bottom_rgt.x;
          bottom_rgt_y = bottom_rgt.y;
          top_lft_x = top_lft.x;
          top_lft_y = top_lft.y;
     public String toString()
          return super.toString() + " coordinates top left= " + top_lft_x + "," + top_lft_y + "and bottom right" +
               bottom_rgt_x + "," + bottom_rgt_y + ")";
     public void is_it_diagonal()
          if(top_lft_x < bottom_rgt_x && bottom_rgt_x > top_lft_x)
               System.out.println("Points are Not Diagonal");
          public double distance()
               distance ();
               return delta;
          public Point move(Point top_lft)
               move();
               bottom_rgt_x += delta;
               bottom_rgt_y += delta;
               return top_lft;
          public void get_other_coords()
               top_rgt.x = bottom_rgt.x;
          top_rgt.y = top_lft.y;
               bottom_lft.x = top_lft.x;
               bottom_lft.y = bottom_rgt.y;
          public void show()
               super.show();
               System.out.println("new coords are :");
               System.out .println ("(" + top_lft_x + "," + top_lft_y + ")");
               System.out .println ("top right(" + top_rgt + ")");
               System.out .println ("(" + bottom_rgt_x + "," + bottom_rgt_y + ")");
               System.out .println ("bottom right(" + bottom_rgt + ")");
import java .awt .Point ;
public class Points extends Shapes
     protected double delta = 0.0;
     protected double x;
     protected double y;
     protected String ashape = "Points";
     public Points( double x, double y)
          super("Points");
          x = x;
          y = y;
     public Points( Point start)
          super("Points");
          x = start.x;
          y = start.y;
     public String toString()
          return super.toString() + "References coordinates(" + x + y + ")";
     public double distance(double x1, double y1 )
          return delta =(Math.sqrt(x - x1) * (x - x1) + (y - y1) *
          (y - y1));
     public Point move(Point pts)
          pts.x += delta;
          pts.y += delta;
          return pts;
     public void show()
          System.out.println("This shape is a" + ashape + "(" +
                              "(" + x+ "," + y + ")");
import java .awt .Point ;
public class Lines extends Points
     double delta = 0;
     protected double x;
     protected double y;
     protected String ashape = "Lines";
     public Lines( double x1, double y1, double x, double y)
          super(x1,y1);
          x = x;
          y = y;
     public Lines(Point start, Point end)
          super(start);
          x = end.x;
          y = end.y;
     public String toString(Point end)
          return super.toString() + "line points = (" + x + "," + y +
               "(" + end + ")";
     public double distance()
          distance ();
          return delta;
     public Point move(Point lines)
          move ();
          return lines;
     public void show()
          System.out.println("This shape is a" + ashape + "(" +
                              "(" + x + "," + y + ")");
import java .awt .Point ;
public class Circles extends Points
protected double radius;
protected double xcenter;
protected double ycenter;
protected String ashape = "Circle";
     public Circles( double x, double y, double cx, double cy, double radians)
          super(x, y);
          xcenter = cx;
          ycenter = cy;
          radius = radians;
     public Circles( Point acenter, Point ref, double radians)
          super(ref);
          xcenter = acenter.x;
          ycenter = acenter.y;
          radius = radians;
     public String toString(Point ref)
          return super.toString() + " reference points (" +
               ref + ")" +
               "center coordinates (" + xcenter + "," + ycenter + ")";
          public double distance(Point ref)
               return (Math.sqrt(ref.x - xcenter) * (ref.x - xcenter)
                         + (ref.y - ycenter) *
          (ref.y - ycenter));
          public Point move(Point center)
               move();
               return center;
          public void show()
               System.out.println("This shape is a" + ashape + "(" +
                              "(" + xcenter + "," + ycenter + ")");

How to call derived class to base class

Hello everybody,
I create a GUi application in java swing. Now i want to navigate between the screen but the timing between the screen is very slow bcoz i imported the class from package to another package. Now i want to extends one package to another package to reduce the navigation time but it saying error bcoz i cant able to call my derived class to base class. if anyone know the answer for this please answer this immediately.
If any other method is there to optimise the navigation time please tell me
by
(kamal)

Sorry, I've got major difficulties understanding your query:
I create a GUi application in java
ication in java swing. ok
Now i want to navigate between
the screenwhat? switch screens? display a different dialog?
but the timing between the screen is very
slowtiming? do you mean the time it takes to display a different dialog?
bcoz i imported the class from package to
another package.how did you come to the conclusion that that is the reason for the slowness? Did you do any profiling or is this just guess-work?

Set fields of derived class in base class constructor via reflection?

Does the Java Language Specification explicitly allow setting of fields of a derived class from within the base class' constructor via reflection? The following test case runs green, but I would really like to know if this Java code is compatible among different VM implementations.
Many thanks for your feedback!
Norman
public class DerivedClassReflectionWorksInBaseClassConstructorTest extends TestCase {
abstract static class A {
    A() {
        try {
            getClass().getDeclaredField("x").setInt(this, 42);
        } catch (Exception e) {
            throw new RuntimeException(e);
static class B extends A {
    int x;
    B() {
    B(int x) {
        this.x = x;
public void testThatItWorks() {
    assertEquals(42, new B().x);
    assertEquals(99, new B(99).x);
}

why not just put a method in the superclass that the subclasses can call to initialize the subclass member variable?In derived classes (which are plug-ins), clients can use a field annotation which provides some parameter metadata such as validators and the default value. The framework must set the default value of fields, before the class' initializer or constructors are called. If the framework would do this after derived class' initializer or constructors are called, they would be overwritten:
Framework:
public abstract class Operator {
    public abstract void initialize();
}Plug-In:
public class SomeOperator extends Operator {
    @Parameter(defaultValue="42", interval="[0,100)")
    double threshold;
    @Parameter(defaultValue="C", valueSet="A,B,C")
    String mode;
    public void setThreshold(double threshold) {this.threshold = threshold;}
    public void setMode(String mode) {this.mode = mode;}
    // called by the framework after default values have been set
    public void initialize() {
}On the other hand, the default values and other metadata are also used to create GUIs and XML I/O for the derived operator class, without having it instantiated. So we cannot use the initial instance field values for that, because we don't have an instance.

Linkage Class / Base Class conflict?

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