import javafx can not be resolved - java

I am using Windows 10 64-bit and eclipse java 2019-06.I have installed jdk 12.0.2 and jre 8u221. I have set environment system path in environment variable to C:\Program Files\Java\jdk-12.0.2\bin.I can easily compile and run java file in windows command prompt. I can not import javafx.
I have used e(fx)clipse (javafx1 in the following picture). I have also tried adding jfxswt.jar into external library(javafx2 in the following picture).
enter image description here

As per this article, Future of JavaFx
Starting with JDK 11, Oracle is making JavaFX
easier to adopt by making the technology available as a separate
download, decoupled from the JDK.
As you mentioned, you are using JDK 12.0.2. JavaFx library are no longer part of JDK, they need to be added separately.
Here you can find official documentation on how to proceed with JavaFX 12 development
Install JavaFx

JFX is not part of JDK since Java 11. They are now distributed as standalone packages. Some reading can be found here
You can either add the OpenJFX libraries by downloading them from here, or you can use another JDK distribution such as Azul, which bundles the OpenJFX with their OpenJDK distributions.

Related

Does SDKMAN! install JRE only or also JDK?

I'm trying to use VisualVM but I'm getting the following error:
You are running VisualVM using Java Runtime Environment (JRE)
I'm using SDKMAN! to manage my Java versions
What should I do to make VisualVM work?
I stumble upon your question while trying to point Spring Tool Suite to the JDK's JRE. sdkman installs the jdk & the JRE.
The confusion is probably because there is no more a jre folder in the jdk as from Java 9 as per this explanation. The important line is:
The JDK and JRE run-time images have been restructured as documented
in JEP 220.
The solution for me was to modify SpringToolSuite4.ini:
-vm
/home/jumping_monkey/.sdkman/candidates/java/11.0.11.hs-adpt/bin

How to fix error while installing NetBeans?

I have installed Java and am trying to install NetBeans 11.3 on my Windows 10 but after I ran the exe. installer, an error message popped up:
An unexpected exception happened in thread main
java.lang.NoClassDefFoundError java/util/jar/Pack200
NetBeans have problems with the jdk-14, because I suppose that you have install the jdk-14 so uninstall it and try it with the jdk-13.0.2.
Sorry, but in my opinion is to install an old version from Java no solution, just because it works. When someone has problems with his Firewall, simply disable the Firewall would also be no solution.
https://www.java.com/en/download/faq/other_jreversions.xml
We highly recommend users remove all older versions of Java from your
system. Keeping old and unsupported versions of Java on your system
presents a serious security risk. Removing older versions of Java from
your system ensures that Java applications will run with the most
up-to-date security and performance improvements on your system.
The "real" solution would be a reprogramming of the NetBeans installer.
This used function was suggested for deprecated on 2018-04-04, which was done on 2018-08-23.
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8200752
The removal was suggested on 2019-10-08, which was done on 2019-12-18.
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8232022
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8232022
We assume that developers who rely on Pack200 have had enough notice about its proposed removal to make alternative arrangements. … We assume that developers who use pack200 to shrink application JARs can switch to either the jlink tool or the jpackage tool to create application-specific runtimes with an optimized form factor.
edit: I solved it this way.
uninstalled JDK 14
installed JDK 13.0.2
installed Apache NetBeans
installed JDK 14
open C:\Program Files\NetBeans\netbeans\etc\netbeans.conf and changed path to JDK
uninstalled JDK 13.0.2
Now NetBeans runs with the JDK 14.
Yes, I got it working as follows from cmd, when referring to older version:
Apache-NetBeans-11.3-bin-windows-x64.exe --javahome "C:\Program Files\Java\jdk-12.0.2"
The https://netbeans.apache.org/download/nb113/nb113.html site now has this
memo:
The installers will not run under JDK 14 because usage is made of the Pack200 Tools and API, for packing and unpacking, which is removed in JDK 14, see JEP 367.
If several JDK versions are installed, then you need to define the environment variable "JAVA_HOME" where to set the path to JDK-12.
Details are described here. (Only in Russian)
An alternate way to Andy's.
(Windows)
1) Right click on "Apache-NetBeans-11.3-bin-windows-x64" installer and select "Create shortcut".
2) Right click on the created shortcut and select "Properties".
3) In the "target" textbox, add your under 14 JDK version path at the end, here is how mine looks like:
C:\Users\userfoldername\Desktop\Apache-NetBeans-11.3-bin-windows-x64.exe --javahome "C:\Program Files\Java\jdk-13"
4) Press Ok when done, double-click on the shortcut and it should install fine now.
Switching to openJDK 12 worked for me too. But instead of uninstalling JDKs or manually changing the env, I use Sdkman.io which works like Node version manager if you have used that. It manages your JDKS for you and offers downloads of different versions (Open, Zulu, Graals) and will switch between them with with just a quick command.
I found a nice solution in 3 steps:
check all versions of the JDK path in Environment variables, if there is an outdated path please remove it and keep the latest version of the Java JDK bin path.
after the second step, please uninstall the Netbeans and re-install the latest version.
Netbeans will found the latest JDK path in case it was jdk14 and choose JDK latest version path for NetBeans.
solved
Just install JRE from oracle. Everthing will run fine. I have the same issue

What are the parameters set by the JRE installer in my linux machine apart from copying JRE files?

I am writing a Java Swing application. I downloaded JRE for Linux platfrom from Oracle website and just bundled this JRE my application.
I have given a launcher script, in which I am referring the bundled JRE bin/java executable. So it works fine.
My question is, what is the difference between installing the JRE by downloading from the Oracle website and this procedure?
What are the extra parameters set by the JRE installer in my Linux machine apart from copying JRE files?
What are the environment variables set and what are the shared libraries copied? Any idea?
It depends a lot on how you install.
First, I assume you are talking about Java 8, since later versions of Java don't come with a separate JRE.
For Oracle Java 8 installations for Linux, there is a choice of rpm or other package installers or the basic Linux manual installation. The latter is described here. As you can see from the documentation, it's just a simple tar.gz which you unzip/untar into a directory of your choice, and that's it. The same as your bundled JRE.
if you want develop a application. you should download jdk, not jre.
jdk: java develop tookit
jre: java runtime.
linux has an old openjdk, but you can download jdk from oracle website. just download a xx.tar.gz, and untar it into:
/usr/java/jdk1.8xx
and set path:
JAVA_HOME=/usr/java/jdk1.8.0_121
CLASSPATH=.:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar
PATH=$PATH:$JAVA_HOME/bin
export JAVA_HOME PATH CLASSPATH

Where to find required JRE files in OpenJDK for an JavaFX application to be wrapped using Launch4j

I'm building a GUI application in Java using JavaFX. So far I've been using Oracle JDK but due to licensing issues, I've decided to move on to OpenJDK or Azul Zulu. They don't come with JavaFX so I built OpenJFX myself on Ubuntu 16.04 (running on WSL).
Now, to wrap the application using Launch4j, I need the only the required JRE files to keep the application size minimum. In Oracle JDK distributions JRE is simply found in JRE folder, however, OpenJDK and OpenJFX have a different structure and I could not find (or missed, my bad) any documentation relevant to my question.
tl;dr: Need the location/path of minimum of required JRE files from OpenJDK and OpenJFX to wrap a cross-platform application using Lanuch4j.

Using Java 1.4 for applet when 1.6 is installed

My Java applet only supports 1.4 java run time(1). I am having one machine on which both Java 1.4 and 1.6 environment is installed. Is there some setting available by which I can make sure my applet will always use Java 1.4 run time when it runs?
We are using key event class private data array bData with the help of Java reflection. The data which is there in this array JDK 1.4 and 1.6 is different in both the version.
A Java application compiled with JDK 1.4 will run on JDK 1.6.
You can compile a Java application with JDK 1.6, but compatible with JDK 1.4 by configuring the 'source level'.
Although you can choose your default JDK to be safe, but it depends on your operating system. If you are on Linux, you can choose between available Java versions using pdate-alternatives --config java command (which will modify some symlinks in the hindsight).
On Windows 7:
Control Panel -> Programs -> Java
Select 'Java' tab, and View the Java Runtime Environment settings.
Ensure that your Java 1.4 entry is selected.
There's a way to force a specific installed version to run, but if one Java plugin replaces the other there might be an issue with this. See linked question for further details.
Force Internet Explorer to use a specific Java Runtime Environment install?
Are there any issues with running the 1.4 code on 1.6? If not, you should be fine. Just avoid using anything in the classpath that changed significantly between these versions. Otherwise, look [here][1]. The codebase download thing is interesting, since it lets you download a different classpath. So, regardless of the JRE version, you could force the download of a 1.4 JRE classpath, which should ensure full compatability.
Edit: found an updated guide to using previous classpaths with newer Java versions in applets, which actually seems to work:
http://download.oracle.com/javase/tutorial/deployment/applet/deployingApplet.html
Edit 2: I actually have it working, but it appears to need to download JRE 1.4 and install it, but then it will run the applet with it automatically. However, this might be suitable for your needs.
http://www.2shared.com/file/bl3Rua2e/applet.html -- extract the archive, and then run index.html inside this. All source code is included.

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