How can I determine if my client is running OpenJDK with a web plugin? I've tried java.version and the rest of the properties listed here.
Running java -version from the terminal works fine, but if I went this route, java would have to be on the user's path, which I don't know if I can trust entirely. Is there any other way to see the string given by java -version programmatically, without shelling out to the command line or terminal?
Right now, when I run System.getProperties().getProperty("java.version"), I get Sun Microsystems Inc.!
You can't do it via system properties, but firefox provides a navigator.plugins array containing all installed plugins. If you check the "name" property of each plugin, you should be able to separate the Sun Java plugin from imitators.
Related
I'm running Leiningen in Counterclockwise in Eclipse (Windows, if it's relevant).
The thing is, when I run Leiningen from the command prompt, it runs just fine. However when I run it inside Eclipse, although it runs fine it haunts me with the following warning:
Java HotSpot(TM) Client VM warning: TieredCompilation is disabled in this release.
The only relevant thing I found on the Internet is this. However the solution doesn't work for me as I don't have this line in lein.bat file. I've tried fiddling with Java options in lein.bat to enable TieredCompilation explicitly with no avail. I'm trying to understand - what's different when Eclipse runs lein, compared to when I run it from the prompt, how does it run it? How do I hide this message?
EDIT: this warning seems to appear only in 32-bit JVM; for anyone having the same problem, using 64-bit JVM solves it. For anyone that as to use 32-bit JVM for whatever reason, I'm still looking for a good solution.
(converted from comment as I have to add additional info)
CCW uses its own version of Leiningen - for example, when I execute lein version from inside CCW I get 2.5.1, but if I drop to the command line and execute the same command I get 2.7.1. In my install (Neon + CCW - couldn't make the standalone CCW install work) there's a leiningen-standalone.jar in C:\eclipse\plugins\ccw.core_0.35.1.STABLE001. There may be a way to get Counterclockwise to use a separate version of Leiningen - perhaps more knowledgeable users will chime in with how to do this.
Also note that in the Windows install of Leiningen the LEIN_JVM_OPTS environment variable isn't defined at all in lein.bat, although it is used when invoking Java. Thus it seems you have two options:
Less-preferred option: edit lein.bat and add the definition of LEIN_JVM_OPTS, probably somewhere near the beginning of the file. This has the disadvantage that when you upgrade Leiningen you'll lose your definition of LEIN_JVM_OPTS and have to find this message again.
More-preferred option: since this is Windows you can go into Control Panel, type "environ" in the search box, then click on on the "Edit environment variables for your account" link which comes up under System (or click on "Edit the system environment variables" if you like). Create a new entry for LEIN_JVM_OPTS, specifying something like
-XX:-TieredCompilation
and you should be good to go. While I don't know for certain if this environment variable is used by the standalone .jar version of Leiningen I'd certainly hope and expect it would be.
Best of luck.
I use cookbooks from https://supermarket.chef.io/cookbooks/java
The code runs on Centos 6, but it doesn't run on windows server.
I get this ERROR
No download url set for java installer
URI::invalidURIError
bad URI(is not URI)
For Windows, you have to provide the Java installation file yourself, i.e. download the installer and put it somewhere locally. Then set node['java']['windows']['url'] to point to the file.
The documentation explains why this is necessary - basically there's no simple way to download the java msi programmatically from Oracle's website.
I am deploying a Java EE project in a server that uses the MCR of Matlab for some image processing functions. I've been trying this for months I can't make it work. The problem is when it is going to uses the MCR it cannot find the .so libraries. I got this error:
javax.servlet.ServletException: Failed to find the library libmwmclmcrrt.so.7.13, required by MATLAB builder JA, on java.library.path. This library is typically installed along with MATLAB or the MCR, its absence may indicate an issue with that installation or r the current path configuration. The MCR version that this component is trying to use is 7.13.
ROOT CAUSE:
java.lang.UnsatisfiedLinkError: Failed to find the library libmwmclmcrrt.so.7.13, required by MATLAB Builder JA, on java.library.path. This library is typically installed along with MATLAB or the MCR, its absence may indicate an issue with that installation or the current path configuration. The MCR version that this component is trying to use is: 7.13.
The servers uses:
Ubutuntu 64 bits.
Netbeans 7.4
Glassfish
java 6 sdk
first it uses MCR 7.13 now it uses MCR 8.1
Things I've already tried:
Setting the environment variables LD_LIBRARY_PATH and XAPPLERSDIR with export:
export LD_LIBRARY_PATH=/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/runtime/glnxa64:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/bin/glnxa64:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/java/jre/glnxa64/jre/lib/amd64/native_threads:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/java/jre/glnxa64/jre/lib/amd64/server:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/java/jre/glnxa64/jre/lib/amd64:$LD_LIBRARY_PATH
export XAPPLRESDIR=/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/X11/app-defaults
Setting the environment variables LD_LIBRARY_PATH and XAPPLERSDIR with setenv:
Command setenv not found
Edit ld.so.conf file and run ldconfig
Add -Djava.library.path=my/path/to/so in glassfish
Add -Djava.library.path=my/path/to/so in Netbeans like says here:
giving 'java.library.path' in netbeans for .dll/.so files
I tried to set environment variables in Netbeans like said in this post: How to set Environment Variable in Netbeans?
But I can't find "Actions"
I tried to set environment variables in Netbeans like said in this post: https://askubuntu.com/questions/267071/ld-library-path-specification
But I can't find "Environment"
I've tried lots of more things that I can't remember and none of them works, it keeps showing the same error (now for version 8.1 instead of 7.13). Please I would I appreciate any help.
I had the same problem working with Linux, Java EE and Matlab. My solution was:
Open a terminal
Log as root $ su and type password
Edit the /etc/enviroment $ gedit /etc/enviroment
Add the needed variables, in our case:
LD_LIBRARY_PATH="/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/runtime/glnxa64:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/bin/glnxa64:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/java/jre/glnxa64/jre/lib/amd64/native_threads:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/java/jre/glnxa64/jre/lib/amd64/server:/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/sys/java/jre/glnxa64/jre/lib/amd64"
XAPPLRESDIR="/usr/local/MATLAB/MATLAB_Compiler_Runtime/v81/X11/app-defaults"
Save the file and reboot.
Start the server as root.
What happened with your other solutions, like the export, was that there was no visibility between the variables that you created and the GlassFish server. Setting variables in the environment will asure you that they are visible from any other program/process.
I have an existing Java program that I am giving to some.... not so technically inclined clients of mine. They use a combination of Linux, Windows, and very few have apple machines, which is why I chose Java to develop the program in. The problem is they keep calling me with errors when they try to launch the program because they do not have a JRE installed. Is there any way to:
Import a lib that will give me some kind of command to check.
Add something to the program that will check for the JRE.
or (and I really don't want to go about this because of the reason I chose java in the first place)
Write something in C++ that will check for the JRE.
My aim:
Check if JRE installed on machine
If yes: Launch program
If no: pop up a message saying "No Java Environment found, downloading from Java website". Then I would take them directly to the link where they hit "run" and it installs.
// i would do something like
if (JRE.exists()) // maybe use a pathname that would only show up if a JRE is installed
{
// launch program
}
else
{
// launch Java installer
}
system.exit(0);
I understand this would be really hard in java (as you cannot run Java programs without a JRE) but I prefer to keep this universal if at all possible.
If there is no easy fix, I'll just make a read-me file that has the link to the java website that checks for a JRE on your system, but the least amount of work the user has to do the better.
I would suggest you use an Java installer like IzPack or other such free tools. Using one of these you can create an installer and also generate a native launcher. This can be configured such as it searches for Java and if not found, it can help the user installing it.
There are developers that also use JSmooth or Launch4J for native launchers.
check for JRE on system
Use deployJava.js as mentioned in the Java Web Start info. page.
..designed to ensure a suitable minimum version of Java is installed before providing a link to a JWS app. or launching an applet.
If it is a rich client desktop app. (e.g. applet or frame), deploy it using Java Web Start.
If you can't go with Java Web Start, although I'd recommend using it, you can write simple scripts to detect Java.
For Windows (.bat):
if not "%JAVA_HOME%" == "" (
"%JAVA_HOME%\bin\javaw.exe" -jar YourApp.jar
) else (
start http://java.com/download/
)
If JAVA_HOME environment variable is defined, then javaw.exe will be started with your application jar file. The javaw.exe executable uses window subsystem thus it runs without console window.
If JAVA_HOME is not set, it will open the Java download page in the default browser.
For more options, you can use JScript; with it you can display a warning to users that Java is not installed and then open the browser for download.
For Linux (.sh):
if [ "$JAVA_HOME" != "" ]; then
$JAVA_HOME/bin/java -jar YourApp.jar &
else
echo JAVA_HOME is not set: Java Runtime Environment (JRE)
echo is not installed your system.
echo Either install it from http://java.com/download/
echo or set JAVA_HOME environment variable.
fi
why don't you just create batch and bash files doing that and ask your customer to run one or the other dependently on the OS
if the JRE is installed on a system, then JAVA_HOME environment variable is set on both Windows and Linux and it contains the path of JRE. You can check if this variable is set and accordingly proceed.
When I want to install oracle weblogic using fmw_12.2.1.0.0_wls.jar file in windows 10, the installation window doesn't be shown automatically and I just get this message in cmd : press any key to exit. why? How can I fix it?
This picture shows my problem:
Could be a problem with your java. Try downloading and installing Oracle's Java 8. FMW 12c is certified with Java 8 and runs best with Oracle's Java - JDK/SDK to be specific. Openjdk is not certified and won't work for an install.
Could also be an issue with your X display. Ensure that you have the display variable correctly set and a Xhost client running. Test your X display with another program to verify functionality. If you have X issues, try unsetting the DISPLAY variable and have it run the character based installer.