Java program kicking out error

[Adam Pritchardson]

My program is kicking out an error and I'm not sure that I know why it is doing it.  I have already tried to debug myself, but the Eclipse IDE doesn't give me any errors.  Any help will be appreciated.
import java.util.Calendar; import java.util.GregorianCalendar; import javafx.scene.layout.Pane; import javafx.scene.paint.Color; import javafx.scene.shape.Circle; import javafx.scene.shape.Line; import javafx.scene.text.Text; public class ClockPane extends Pane { private int hour; private int minute; private int second; public ClockPane() { setCurrentTime(); } /** Construct a clock with specified hour, minute, and second */ public ClockPane(int hour, int minute, int second) { this.hour = hour; this.minute = minute; this.second = second; } /** Return hour */ public int getHour() { return hour; } // Set a new hour public void setHour(int hour) { this.hour = hour; paintClock(); } // Return minute public int getMinute() { return minute; } // Set a new minute public void setMinute(int minute) { this.minute = minute; paintClock(); } // Return second public int getSecond() { return second; } // Set a new second public void setSecond(int second) { this.second = second; paintClock(); } /** Set the current time for the clock */ public void setCurrentTime() { // Construct a calendar for the current date and time Calendar calendar = new GregorianCalendar(); // Set current hour, minute and second this.hour = calendar.get(Calendar.HOUR_OF_DAY); this.minute = calendar.get(Calendar.MINUTE); this.second = calendar.get(Calendar.SECOND); paintClock(); // Repaint the clock } /** Paint the clock */ private void paintClock() { // Initialize clock parameters double clockRadius = Math.min(getWidth(),  getHeight()) * 0.8 * 0.5; double centerX = getWidth() / 2; double centerY = getHeight() / 2; // Draw circle Circle circle = new Circle(centerX, centerY, clockRadius); circle.setFill(Color.WHITE); circle.setStroke(Color.BLACK); Text t1 = new Text(centerX - 5, centerY - clockRadius + 12, "12"); Text t2 = new Text(centerX - clockRadius + 3, centerY + 5, "9"); Text t3 = new Text(centerX + clockRadius - 10, centerY + 3, "3"); Text t4 = new Text(centerX - 3, centerY + clockRadius - 3, "6"); // Draw second hand double sLength = clockRadius * 0.8; double secondX = centerX + sLength * Math.sin(second * (2 * Math.PI / 60)); double secondY = centerY - sLength * Math.cos(second * (2 * Math.PI / 60)); Line sLine = new Line(centerX, centerY, secondX, secondY); sLine.setStroke(Color.RED); // Draw minute hand double mLength = clockRadius * 0.65; double xMinute = centerX + mLength * Math.sin(minute * (2 * Math.PI / 60)); double minuteY = centerY - mLength * Math.cos(minute * (2 * Math.PI / 60)); Line mLine = new Line(centerX, centerY, xMinute, minuteY); mLine.setStroke(Color.BLUE); // Draw hour hand double hLength = clockRadius * 0.5; double hourX = centerX + hLength * Math.sin((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)); double hourY = centerY - hLength * Math.cos((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)); Line hLine = new Line(centerX, centerY, hourX, hourY); hLine.setStroke(Color.GREEN); getChildren().clear(); getChildren().addAll(circle, t1, t2, t3, t2, sLine, mLine, hLine); } @Override public void setWidth(double width) { super.setWidth(width); paintClock(); } @Override public void setHeight(double height) { super.setHeight(height); paintClock(); } }

import javafx.application.Application; import javafx.geometry.Pos; import javafx.stage.Stage; import javafx.scene.Scene; import javafx.scene.control.Label; import javafx.scene.layout.BorderPane; public class DisplayClock extends Application { @Override // Override the start method in the Application Class public void start(Stage primaryStage) { // Create a clock and a label ClockPane clock = new ClockPane(); String timeString = clock.getHour() + ":" + clock.getMinute() + ":" + clock.getSecond(); Label lblCurrentTime = new Label(timeString); // Place clock and label in border pane BorderPane pane = new BorderPane(); pane.setCenter(clock); pane.setBottom(lblCurrentTime); BorderPane.setAlignment(lblCurrentTime,  Pos.TOP_CENTER); // Create a scene and place it in the stage Scene scene = new Scene(pane, 250, 250); primaryStage.setTitle("DisplayClock"); // Set the stage title primaryStage.setScene(scene); // Place the scene in the stage primaryStage.show(); // Display the stage } public static void main(String[] args) { Application.launch(args); } }

[Ron McLeod]

Adam Pritchardson wrote:My program is kicking out an error and I'm not sure that I know why it is doing it.

What specifically is the error?  Is there any stack trace or other details that you can share?

[Prasad Saya]

My program is kicking out an error ...

Please tell what is that kicked out error?

[Adam Pritchardson]

Sorry, I should have include the error message in Eclipse. It is below:

Exception in Application start method
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(Unknown Source)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(Unknown Source)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at java.base/sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: Children: duplicate children added: parent = ClockPane@95b12a3
at javafx.graphics/javafx.scene.Parent$3.onProposedChange(Unknown Source)
at javafx.base/com.sun.javafx.collections.VetoableListDecorator.addAll(Unknown Source)
at javafx.base/com.sun.javafx.collections.VetoableListDecorator.addAll(Unknown Source)
at ClockPane.paintClock(ClockPane.java:111)
at ClockPane.setCurrentTime(ClockPane.java:68)
at ClockPane.<init>(ClockPane.java:15)
at DisplayClock.start(DisplayClock.java:13)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(Unknown Source)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$11(Unknown Source)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$9(Unknown Source)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(Unknown Source)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(Unknown Source)
... 1 more
Exception running application DisplayClock

[Adam Pritchardson]

I don't really know how to read that error, I can see that the first line states there is an exception in the start method, but I don't know what the exception is. As I said the Eclipse IDE isn't giving me any help.

[Ron McLeod]

I would start by looking at Caused by: java.lang.IllegalArgumentException: Children: duplicate children added: parent = ClockPane@95b12a3

Where do you add children to ClockPane?

[Adam Pritchardson]

Ron McLeod wrote:I would start by looking at Caused by: java.lang.IllegalArgumentException: Children: duplicate children added: parent = ClockPane@95b12a3

Where do you add children to ClockPane?

Thank you.  I found my duplicate argument. It was at line 111.  I looked over that thing 1000 times and didn't find it until tonight.  Thank you again.

[Ron McLeod]

Adam Pritchardson wrote:I found my duplicate argument. It was at line 111.

Great  

Since you are using Eclipse, there would have been some warnings present in the IDE: a yellow triangle icon in the gutter, a wavy yellow line on line 85, and a warning of an unused local variable in the Problems view.  While these don't point directly to the problem, you would have figured-out your problem quickly if you would have investigated what they were trying to tell you.

[Adam Pritchardson]

Thank you agin