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Error Writing a Bouncing Ball Program  RSS feed

 
Greenhorn
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My program won't successfully compile when I write my bouncing ball application and I'm not sure where to begin repairs.
Staff note (Liutauras Vilda):

Fixed wrongly used code tags

 
Marshal
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David Alcorn wrote:My program won't successfully compile when I write my bouncing ball application and I'm not sure where to begin repairs


As for a start, probably a good idea is to share the compile time error message. Please don't rephrase, but rather copy and paste it - there is important information, which tells you what exactly is wrong.
 
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It is always best to debug the first error first. One error can cause a cascade of other errors so if you clean up the first one often others will go away as well. Keep a close eye on the line numbers in the error messages.
 
David Alcorn
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java.lang.NoClassDefFoundError: MyRectangle2D
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
at java.lang.Class.getMethod0(Class.java:3018)
at java.lang.Class.getMethod(Class.java:1784)
at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: MyRectangle2D
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 7 more
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" C:\Users\School\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 3 seconds)
 
David Alcorn
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Compiler Error

C:\Users\School\Documents\NetBeansProjects\BouncingBall\src\bouncingball\BouncingBall.java:124: error: cannot find symbol
            public static MyRectangle2D getRectangle(ArrayList list){
  symbol:   class MyRectangle2D
  location: class BouncingBall
C:\Users\School\Documents\NetBeansProjects\BouncingBall\src\bouncingball\BouncingBall.java:132: error: cannot find symbol
            public static MyRectangle2D getRectangle(double[][] points){
  symbol:   class MyRectangle2D
  location: class BouncingBall
C:\Users\School\Documents\NetBeansProjects\BouncingBall\src\bouncingball\BouncingBall.java:67: error: cannot find symbol
                MyRectangle2D rectangle = getRectangle (list);
  symbol:   class MyRectangle2D
  location: class BouncingBall.View
C:\Users\School\Documents\NetBeansProjects\BouncingBall\src\bouncingball\BouncingBall.java:137: error: cannot find symbol
                return new MyRectangle2D((minX+maxX)/2,(minY+maxY)/2,maxX-minX,maxY-minY);
  symbol:   class MyRectangle2D
  location: class BouncingBall
Note: C:\Users\School\Documents\NetBeansProjects\BouncingBall\src\bouncingball\BouncingBall.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
4 errors
C:\Users\School\Documents\NetBeansProjects\BouncingBall\nbproject\build-impl.xml:930: The following error occurred while executing this line:
C:\Users\School\Documents\NetBeansProjects\BouncingBall\nbproject\build-impl.xml:270: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 4 seconds)
 
Master Rancher
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hi David,

in your code you are referring often to a class called 'MyRectangle2D'. The compiler complains that it cannot find it, and I cannot find it too in your code. Do you have such a class, somewhere?
 
It is sorta covered in the JavaRanch Style Guide.
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