Develop Reference

I dont' know how to install libXtst.so.6 library required for my application deployed on heroku

I have made a spring-boot app printing some created files in Microsoft Word. Locally it works fine. However when i try to print them via an app deployed on heroku such a problem occurs:
There was an unexpected error (type=Internal Server Error,
status=500). /app/.jdk/jre/lib/amd64/libawt_xawt.so: libXtst.so.6:
cannot open shared object file: No such file or directory
From what i looked up in google i believe i should install somewhere libxrender1:i386 libxtst6:i386 libxi6:i386. I just don't know where to find it and where exactly should i put it. I would be really happy if someone could help me sort this out.

From what i looked up in google i believe i should install somewhere libxrender1:i386 libxtst6:i386 libxi6:i386.
That is incorrect: the reference to the libXtst.so.6 comes from .../jre/lib/amd64/libawt_xawt.so, so you need a 64-bit version of libXtst.so.6, not a 32-bit one.
I just don't know where to find it and where exactly should i put it.
The answer is: use package manager that comes with your system (you didn't tell us what OS you are running).
This could be sudo apt install libxtst6 (Ubuntu / Debian), or sudo yum install libXtst (CentOS or RedHat or Fedora), or something else.

Serial link error and bad path jre 1.7.0_15 32-bi

Trying to make an old java game run on the original PC both ca 2012. JRE 1.7.0_15 (32bit) runs on linux (Puppy 6.3, 32 bit). I can configure the game with java but the next console command to start the game fails with
Exception in thread "AWT-EventQueue-O" java.lang.Unsatisfied LinkError: no serial in java.library.path
...and then more errors.
I don't know java or java syntax. Can you tell from this info what I can type in urxvt console so it finds the serial link? Java was installed clean with the Puppy Package Manager, although a few shared libraries report missing. I found those files in other parts of code and online, but have no clue what to do with them so they're found properly or if that's even the problem.
Mine seems to be a common noob issue, but because I don't know what mounts and where, even the right command will fail without typing the true folder names and addresses which I don't have. Can you tell from the error image? Thank you.

Minecraft Forge hat is causing this error when I run `./gradlew wrapper`?

I'm having quite a bit of trouble with ./gradlew. I am trying to make a 1.14.4 mod, and have been having a lot of problems with gradle, but I've finally got gradle working (an error in my build.gradle code). I'm on a Mac, and my friend (with whom I am building the mod) is not, and running
./gradle wrapper
works fine on his computer but not on mine. It must be a system issue, but I'm really not sure. The error I keep getting is:
Could not create service of type ScriptPluginFactory using BuildScopeServices.createScriptPluginFactory().
> Could not create service of type FileHasher using BuildSessionScopeServices.createFileSnapshotter().
I've looked online, and all of the work-arounds I have found doesn't help me. Running ./gradlew wrapper with --info I get this. Running with --stacktrace, I get this. Finally, with --debug I get this. I don't know if these are helpful (I'm sure they are, if you know what to look for).
Any insights into what on earth is causing this is greatly appreciated!
P.S.: my made-up username in the pastebin links is drdeducer :)
P.P.S.: it isn't just ./gradlew wrapper that doesn't work; it is ./gradlew <anything>—even just ./gradlew!

Found the problem for me. In the process of trying to initially get gradle working, I added touch ~/.gradle/gradle.properties and specified org.gradle.java.home=/Library/Java/JavaVirtualMachines/jdk-12.jdk/Contents/Home. Typing /usr/libexec/java_home -V you will get a list of your Java versions, so in my local gradle.properties, I had to specify a Java version less than 11 (it ended up being open adoptopenjdk-8.jdk). To see Java versions, type brew search java, and then brew cask install <desired java version> (for mac users).

Java is not working in my PC

I had installed Java in my PC and it was working perfectly. Suddenly something went wrong and now I m not able to open swing applications and its showing the error 'Java not found'. But I can run the Eclipse IDE which also needed Java to run. So I decide to reinstall the Java, but when I tried to uninstall the Java it shows the Error 1723 - There is a problem with this Windows Installer Package. So I have installed a new JDK in another location and set the PATH. Still I am not able to run the Swing application.
Can anybody help me on this?

How are you running your swing application?
If it's from the command line like java mySwingApp and you're getting java not found then your PATH isn't set properly. Make sure that the java/bin directory is on your PATH not just the top level directory. You can test your PATH by just typing java in a console window - it should print the java help page.
If you're not running from a terminal like above, then you may need to set a JAVA_HOME environment variable which points to your java installation folder. Here's a tutorial on setting JAVA_HOME
Setting JAVA_HOME
Hope this helps,
Will

This is close to jakob's answer, about trying to get your Java install setup correctly again, just with a little more detail.
I had a similar problem on my Windows 7 box where I was trying to uninstall Java and do a clean install of a newer version. Something got messed up and I would get the 1723 error message during the uninstall and attempted reinstall. Here's information about how I was able to fix the problem, and maybe this will help you:
Look at the log files for the uninstall/reinstall. On Windows 7 they can be found at c:\users\username\AppData\Local\Temp\
The java_install.logdidn't show any extra information, but I had several MSI##### log files that contained error messages about the failed uninstall. The message was: Error 1723.There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run. Contact your support personnel or package vendor. Action UninstallJRE, entry: MSIUninstallJRE, library: C:\Program Files\Java\jre6\bin\regutils.dll
There was indeed no regutils.dll file, and not even the bindirectory was there. So I copied over a regutils.dll file from another computer, ran the uninstaller, and it worked. Then the new clean install of Java also worked.
So take a look at your logfiles and hopefully that will give you more detailed information about the 1723 error.

This usally happens when you delete Java files manually.
If you try to uninstall Java and it fails, it generates a log file.
Should be in C:\Users[Username]\AppData\Local\Temp
Almost at the end the missing file(s) can be found.
Try to copy that file(s) from a working installation to your computer.
Then you should be able to uninstall your Java and install a new version.

Java Web Start Not Launching Problem

I've just install New OS windows 7 64bit, After installed java.
I couldn't launch any Java Web Start application from my browser (by downloading and launching a *.jnlp file). When I try to launch an app, the loading cursor spinning for 10-20 seconds then nothing happen. I am getting frustrated with this issue!
Does any one know how can i fix it ?

You can try to download the JNLP file localy and starts it using a command : javaws file.jnlp
you will have more informations about the potential errors.

JNLP is a little annoying initially if you don't get it right. I had the same experience, follow this tutorial, it works like a charm.
Also, please post some error/warning message. Your question is very broad.