With the latest update to Apple's Java 6 on Lion, not only did it disable web browser support, it also disabled Java Web Start. I use javaws with an app that requires Java 6 and 32-bit. Java 6 is still present on my system, but javaws doesn't work:
James-Babkas-iMac:~ jimbabka$ java -version
java version "1.6.0_37"
Java(TM) SE Runtime Environment (build 1.6.0_37-b06-434-11M3909)
Java HotSpot(TM) 64-Bit Server VM (build 20.12-b01-434, mixed mode)
James-Babkas-iMac:~ jimbabka$ javaws http://foo.bar.org/bgameui/bgameui.jnlp
No Java runtime present, requesting install.
Unable to locate a Java Runtime to invoke.
When I run the javaws command, I get a popup message that directs me to an Oracle web page where I can download 64-bit Java 7, which is of no use to me. Is there any way to get javaws working with 32-bit Java 6 again?
i fixed the same problem. After updating yesterday to the latest 1.6.0_37 my javaws did not start anymore (same message as yours).
So let's check first where your javaws is taken from:
which javaws
It will answer you either with nothing (then it is not set at all) or it might point to a symlink (just like on my PC;) which starts a wrong javaws. e.g. from the folder /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands
Try to start your javaws from all folder(s) you find javaws:
/System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands
/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/
/System/Library/Java/Support/Deploy.bundle/Contents/MacOS
(use sudo for testing, e.g. sudo /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/javaws
)
For me it worked from the 2nd folder...
Then you may point a javaws (e.g. /usr/bin/javaws) executable to that javaws (sudo link /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/javaws /usr/bin/javaws)
P.S. At other forums i found that you may have to give additional read (maybe write) rights to your JAVA folders in case the javaws does not start without sudo.
P.S.2: you might want to use a tool like EasyFind to find "hidden" content (which you do not see with Finder)
来源：https://stackoverflow.com/questions/13004854/is-there-any-way-to-reenable-javaws-with-java-6-on-osx-lion