Develop Reference

jpackage command is not recognized

I am trying to package a jar file into an executable file using the jpackage tool in Java, but the command is not recognized in the command prompt using Windows 10 and Java version:
> java --version
java 17.0.1 2021-10-19 LTS
Java(TM) SE Runtime Environment (build 17.0.1+12-LTS-39)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.1+12-LTS-39, mixed mode, sharing)
I have the full JDK installed and the command javac is recognized.
I checked my computer with the "where java javac jpackage" command and it only found the first two in the CommonFiles folder.
I looked in the folder path "ProgramFiles\Java\jdk-17.0.1\jmods" and both the "jdk.jlink.jmod" and "jdk.jpackage.jmod" files are present.
Can someone please help me figure out why the tool isn't recognized by Windows?

I found the issue to be the way my Environment Variables were set up for Java. To fix my problem, I went into the JAVA_HOME variable and changed the entry from
C:\ProgramFiles\Java\jdk-17.0.1\lib
to
C:\ProgramFiles\Java\jdk-17.0.1
Next I updated the path variable to include "%JAVA_HOME%\bin". Before I had it listed as C:\ProgramFiles\Java\jdk-17.0.1\bin. Both of these changes were made under the System variables using the "Edit" button. I want to thank dave_thompson_085 for pointing me in the right direction.

Failed to find Java VM

I've always used Google2SRT, a light software to download subtitles from Youtube. Now it no longer works: "Startup Error: Failed to find Java VM".
I have Java installed, I have Netbeans installed and working, I have never had any Java related issues.
I've tried reinstalling everything, I've tried creating a JAVA_HOME and JRE_HOME System variable and pointing it to "C:\Program Files\Java\jre1.8.0_191" according to this tutorial: https://confluence.atlassian.com/doc/setting-the-java_home-variable-in-windows-8895.html
It felt odd because I didn't even had this environment variable previously. I have no idea what's the issue.
I've tried uninstalling Netbeans and other programming tools as well.
I'm on Windows 7 x64.
java -debug -version > "%userprofile%\desktop\javaDebug.log" 2>&1 returns:
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
I have also tried setting maximum heap size in _JAVA_OPTIONS
System Variables

Just go to the install dir (e.g. C:\Program Files (x86)\Google2SRT), open a cmd.exe, cd to the above folder and type java -jar Google2SRT.jar. You don't need the .exe
This should work, provided you have java installed. Check by typing java -version in the cmd.

Java Home not define (wso2ei-6.4.0 installation)

I am trying to install wso2ei-6.4.0, but it will not run due to the following error messages. I am running a RPi with Debian
Error: JAVA_HOME is not defined correctly.
CARBON cannot execute java
I have executed Java -verison and have the following return
java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) Client VM (build 25.65-b01, mixed mode)
I know the java directory, using Java -which
/usr/bin/java
How do I run Java from any of the directory to execute the installation of wso2ei-6.4.0?

After some time and reading, I managed to add the following into ~/.bashrc:
export JAVA_HOME="/usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt"
export PATH=$PATH:$JAVA_HOME/bin
Note the arm32 directory for the jdk

Try this (as root user):
export JAVA_HOME=/usr/bin/java
Does this solve your issue?

Running Netbeans for Java

I have a problem with running Netbeans for Java development..
When I try to run it I get
I checked the config located in <netbeans_dir>/etc/netbeans.conf and found following setting:
netbeans_jdkhome="/usr/"
So, I checked java and javac:
>>java -version
openjdk version "1.8.0_151"
OpenJDK Runtime Environment (build 1.8.0_151-8u151-b12-0ubuntu0.16.04.2-b12)
OpenJDK 64-Bit Server VM (build 25.151-b12, mixed mode)
>>whereis java
java: /usr/bin/java /usr/share/java /usr/share/man/man1/java.1.gz
>>javac -version
javac 1.8.0_151
>>whereis javac
javac: /usr/bin/javac /usr/share/man/man1/javac.1.gz
So I updated netbeans_jdkhome to /usr/bin/javac. Now, when I try to run Netbeans I get
Cannot find java. Please use the --jdkhome switch.
I also tried to reinstall Java according to this instruction but once I did and changed jdkhome to /usr/lib/jvm/java-8-openjdk I still get Cannot find java.
What should I enter to run Netbeans properly?

Tools -> Java Platforms -> Add platform should display something like this:
Notice that Platform folder has small rectangle that indicates it can be chosen.

java version value is different with java and javac

I am getiing java versions different with java command and javac command
java -version
java version "1.8.0"
Java(TM) SE Runtime Environment (build 1.8.0-b132)
Java HotSpot(TM) Client VM (build 25.0-b70, mixed mode, sharing)
javac -version
javac -version
javac 1.6.0_18
where java
C:\Windows\System32\java.exe
C:\Program Files\Java\jdk1.6.0_18\bin\java.exe
path is set to 1.6 but it is picking 1.8
suggest me how to get this resolved.

This is cause by the extremely annoying habit of the Java installer to copy java.exe andjavaw.exe to C:\Windows\System32\java.exe when you choose to install the "public jre" (but because that's the JRE, of course no javac.exe is copied).
And because System32 comes early in the PATH java.exe from there will be used (and before the regular JDK installation will no be searched for java.exe). But as there is no javac.exe in the JRE, that in turn is used from your JDK.
The public JRE is only needed for the browser Java plugin. In 2014 I consider the Java plugin to be dead and (I think) Oracle should change the JDK installer to not install that automatically.
Actually I consider this behaviour a bug to be honest. No installer should copy files to system32