Re: Newbie Question: Help using JavaFX on Java 7 for Mac OS X 10.7.5...
On 10/1/2012 9:27 AM, piscesboy wrote:
On Sunday, September 30, 2012 8:33:32 PM UTC-4, Lew wrote:
Knute Johnson wrote:
piscesboy wrote:
I just downloaded and installed the Java7 update 7 JDK for Mac
OS X via the convenient .dmg installer on the Oracle website.
JavaFX SDK is supposed to be included
I want to get started on some example JavaFX applications...a
simple HelloWorld app to get started using it and to verify
that JavaFX works on my system. Here's the code for
HelloWorld.java:
. . .
HelloWorld.java:2: error: package javafx.scene does not exist
import javafx.scene.Group;
^
HelloWorld.java:3: error: package javafx.scene does not exist
. . .
It is obvious that it is not finding the JavaFX library to
compile. I did a search and found that the jfxrt.jar file is
required to compile and run it. But it is located inside of the
folder:
/Library/Java/JavaVirtualMachines/jdk1.7.0_07.jdk/Contents/Home/jre/lib
which is inside of the JDK virtual machine folder for Java 7. I don't
think there is any magic classpath command needed to compile this simple
program but I could be wrong.
Clearly.
Yes you need the magic CLASSPATH to compile it. I don't know why
when
the put FX in the JDK and JRE that it isn't already in the
classpath but
it isn't. So just add it to your CLASSPATH and it will work just
fine.
This is one of the rare use cases where it actually makes sense to
put the JAR
in the "CLASSPATH" environment variable (along with "."). Doing
this has perils,
including necessitating the explicit mention of "." as a classpath
element.
Under most circumstances one would eschew "CLASSPATH" in favor of
the more
flexible and less damaging "-classpath" or "-cp" command-line
parameter.
However, when something is so much to be desired as a routine part
of your
build all the time as JavaFX might be in this instance, then the
use of
either "CLASSPATH" or even (gasp!) extension libraries becomes an
option.
Whatever you choose, make sure you have actually RTFMed on tools
classpaths.
--
Lew
I compiled with the -cp option and now it compiles fine...but now it
fails to run when I invoke:
java HelloWorld
I get:
Exception in thread "main" java.lang.NoClassDefFoundError:
javafx/application/Application at
java.lang.ClassLoader.defineClass1(Native Method) at
java.lang.ClassLoader.defineClass(ClassLoader.java:791) at
java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71) at
java.net.URLClassLoader$1.run(URLClassLoader.java:361) at
java.net.URLClassLoader$1.run(URLClassLoader.java:355) at
java.security.AccessController.doPrivileged(Native Method) at
java.net.URLClassLoader.findClass(URLClassLoader.java:354) at
java.lang.ClassLoader.loadClass(ClassLoader.java:423) at
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at
java.lang.ClassLoader.loadClass(ClassLoader.java:356) at
sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:480)
Caused by: java.lang.ClassNotFoundException: javafx.application.Application
at java.net.URLClassLoader$1.run(URLClassLoader.java:366) at
java.net.URLClassLoader$1.run(URLClassLoader.java:355) at
java.security.AccessController.doPrivileged(Native Method) at
java.net.URLClassLoader.findClass(URLClassLoader.java:354) at
java.lang.ClassLoader.loadClass(ClassLoader.java:423) at
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at
java.lang.ClassLoader.loadClass(ClassLoader.java:356)
Again...this seems to be a missing class definition problem...which
leads me to believe there is a deeper flaw in how Java7 is set up in
my machine.
I followed the instructions for downloading and installing Java7
update 7 from the Oracle website, I used the Java Preferences
Application to set my default JDK to jdk 1.7.0 as per the
instructions, but now it's having all these different classpath
issues that do not happen when I use the standard Java 6 JDK from the
Apple vendor as opposed to the Oracle vendor Java 7 JDK.
I guess I should have been more complete, if you need the magic to
compile, you will need the magic to run it too.
--
Knute Johnson