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How to launch locally built metals language server?

I am trying to set up emacs as scala editor. To that end i am trying to install metals for corresponding modes to work.
However, for some reason or another, metals either failed to install from emacs, or when installed with Coursier, were not responsive from emacs.
So, to explore all the options i decided to use metals source code (from Github? but i have run into the issue of being unable to properly utilize them.
What can i do to make metals available to emacs from the sources?
Currently, i have tried building them with
sbt publishLocal
and then trying to run the jar that was generated, with predictable result:
Exception in thread "main" java.lang.NoClassDefFoundError:
scala/collection/Seq at scala.meta.metals.Main.main(Main.scala)
Caused by: java.lang.ClassNotFoundException: scala.collection.Seq at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at
java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
... 1 more
Process metals stderr finished Exception in thread "main"
java.lang.NoClassDefFoundError: scala/collection/Seq at
scala.meta.metals.Main.main(Main.scala) Caused by:
java.lang.ClassNotFoundException: scala.collection.Seq at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at
java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
... 1 more
Process metals stderr finished
In my system i have installed with sbt, as suggested by the instructions on scala website.
How should i setup the system so that metals could be launched and used?

You shouldn't need to compile Metals from sources just to use it from Emacs. Check the official documentation: Emacs | Metals, especially the requirements and installation sections. It mentions
Next you have to install metals server. Emacs can do it for you when lsp-mode is enabled in a scala buffer or via lsp-install-server command. Also you can do it manually executing coursier install metals and configuring $PATH variable properly.
If you have problems with the installation, try asking on Scalameta Discord for help. There is a dedicated #emacs-users channel as well.
That said, if you still want to use a locally published Metals artifact for whatever other reason (e.g. contributing to the Metals code and testing changes locally), you should be able to do that. The contributing documentation describes how to work with the codebase and test your local Metals version.
In short, after you ran sbt publishLocal, you need to update the server version setting in your editor and run the Metals: Restart server command. It should pick up the locally published version.

Issue with mySQL connection after moving java program from one computer to another [duplicate]

When connecting to MySQL, I get an error (see below).
Click here for code
I get this output:
run:
Now connecting to databse...
java.sql.SQLException: java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.lang.Long
java.sql.SQLException: java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.lang.Long
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:988)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:974)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919)
at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1062)
at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3556)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2513)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2283)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:822)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:404)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:317)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at dbms_basic.Dbms_Basic.main(Dbms_Basic.java:28)
Caused by: java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.lang.Long
at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1007)
... 15 more
BUILD SUCCESSFUL (total time: 0 seconds)
How can I solve this?

Your error clearly says casting is not possible, because a java.math.BigInteger class instance is not an instance of java.lang.Long class.
Now the question arises who is doing casting at what level, when we ask the JDBC driver to make a connection, it is doing lot of work behind the scene before it actually give us back the proper working object of connection.
The problem seems with your version of MySQL in combination with your version of mysql-connector.jar. Try a newer version of MySQL Connector/J (see https://dev.mysql.com/downloads/connector/j/ for the latest version), for example upgrade to 5.1.47 or 8.0.12 if you are using an older version.

This issue is not there with 5.1.45 as mentioned in the above comments. Available to download at,
https://repo1.maven.org/maven2/mysql/mysql-connector-java/5.1.45/

Another way, because changing the version from mysql does not worked for me, for help another people:
Long.parseLong(String.valueOf(item[0]);

There is a miss-match between your MySQL version, which might be the latest 8.0.19, but the MySQL driver file is older version may be 5.1.23, which is generally available with the NetBeans IDE. To overcome this, download the mysql-connector-java-5.1.48.jar from this link in your PC download connector/j 5.1.48 zip file
(4.6MB)
Now right-click on project name in the netbeans IDE, go to services, in that choose 'Libraries', in it choose 'Add library', then don't opt for available libraries( the drop-down menu will list a JDBCDriver file which has 'mysql-connector-java-5.1.23.jar' file inside it, which is an older version, this is causing the miss-match). Therefore, instead click on 'Create Library', now give it any name of your choice, then click the create button, a browse window will pop-up, go to the directory where you have downloaded the 'mysql-connector-java-5.1.48.zip' folder, open it and select the java jar file 'mysql-connector-java-5.1.48.jar' and click 'ok'. The library folder of your project tree will now show 'JDBCDriver-mysql-connector-java-5.1.48.jar' added in the list of libraries(JDK and Tomcat) . Now try connecting to your database again by clicking on the 'run' button, go to the JSP link, and you see that this time you are connected.

For me updating the connector wasn't enough, I also had to complete my DriverManager.getConnection() url parameter with all the arguments, even if the error message was not mentionning this issue.
In my case this parameters were needed :
"jdbc:mysql://127.0.0.1:3306/database?zeroDateTimeBehavior=convertToNull&serverTimezone=UTC"
Connector : mysql-connector-java-8.0.17.jar
mysql version : 8.0.17
Using java on netbeans.

This is a common issue when you use outdated/unsupported mysql connector driver. If youre using x86 version of Netbeans, your driver will usually be found in the Program(x86) folder an not the Program folder. something like this "C:\Program Files (x86)\MySQL\Connector J 8.0\mysql-connector-java-8.0.23.jar"

can't connect Mysql to NetBeans(in windows os)

I'm having problem connecting MySQL to Java. I haven't found a driver for windows and was told to choose platform independent.
I'm using NetBeans ide 8.2 and MySQL server 8.0.13 and MySQL Workbench 8.0.13 I've tried to download older versions of drivers to see if it would work but it's just the same result:
java.lang.ClassNotFoundException:com.mysql.cj.jdbc.Driver
the records aren't displayed in the output when I run
am I missing something? do I have to do something other than adding the driver to libraries in NetBeans and writing the connection code? please help me I'm new to this and I need help. Thank you
this is the table in MySQL
this is the connection code in NetBeans

I agree with f1sh that your code looks OK, and also that you don't need the Class.forName() line in your code. I also agree that option Platform Independent is the correct choice of operating system for Windows when downloading the driver.
However, your screenshot unfortunately doesn't show the file extension of the driver that you added under the Libraries node. Can you confirm that the file's extension is jar, not zip or tar?
Downloading the MySQL driver creates a zip or tar file (depending on which option you picked), but you have to unzip that to access the actual driver named mysql-connector-java-8.0.13.jar, and that is the file you must add to your project:
If I include the Class.forName() call, and add the zip instead of the jar to to a simple test project I get exactly the same error as you in NetBeans:
run:
Exception in thread "main" java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at jdbcselecttest.JdbcSelectTest.dbQuery(JdbcSelectTest.java:31)
at jdbcselecttest.JdbcSelectTest.main(JdbcSelectTest.java:25)
C:\Users\johndoe\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 0 seconds)
It's worth noting that without the Class.forName() call the error changes to this:
run:
java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/ebookshop?useSSL=false
at java.sql.DriverManager.getConnection(DriverManager.java:689)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at jdbcselecttest.JdbcSelectTest.dbQuery(JdbcSelectTest.java:32)
at jdbcselecttest.JdbcSelectTest.main(JdbcSelectTest.java:25)
BUILD SUCCESSFUL (total time: 0 seconds)
And if I remove the zip file, and add the jar, file everything works.
If you are already correctly using the jar file then there are further options to explore, but that seems like the mostly likely cause of your problem.

Jenkins windows ssh slave access denied

I want to build my projects on a Windows machine, so I created a slave there. First we tried the standard java application runner, but our build sets up its own environment and it always ended up deleting the existing Java installation, not giving any proper error messages, but failing. Then I switched to using Cygwin sshd and have Jenkins log in via ssh. This works for the connection (just as the standard method worked), but when I ran the build then it failed again to install the jdk. I ended up running the following command by hand:
C:\jenkins\tools\hudson.model.JDK\Latest\jdk.exe ADDLOCAL="ToolsFeature" REBOOT=ReallySuppress INSTALLDIR=C:\jenkins\tools\hudson.model.JDK\Latest /L
This is the same as Jenkins would run, but without the /s (silent) option. Now when I run the build, I get the following error:
Building remotely on jenkins-slave-win64 (Johnny5) (windows) in workspace C:\jenkins\workspace\continuous.xill
java.io.IOException: remote file operation failed: C:\jenkins\tools\hudson.model.JDK\Latest at hudson.remoting.Channel#200354fa:jenkins-slave-win64 (Johnny5): java.nio.file.AccessDeniedException: C:\jenkins\tools\hudson.model.JDK\Latest\bin\java.exe
at hudson.FilePath.act(FilePath.java:987)
at hudson.FilePath.act(FilePath.java:969)
at hudson.FilePath.deleteRecursive(FilePath.java:1171)
at hudson.tools.JDKInstaller.performInstallation(JDKInstaller.java:130)
at hudson.tools.InstallerTranslator.getToolHome(InstallerTranslator.java:68)
at hudson.tools.ToolLocationNodeProperty.getToolHome(ToolLocationNodeProperty.java:108)
at hudson.tools.ToolInstallation.translateFor(ToolInstallation.java:206)
at hudson.model.JDK.forNode(JDK.java:132)
at hudson.model.AbstractProject.getEnvironment(AbstractProject.java:360)
at hudson.model.Run.getEnvironment(Run.java:2234)
at hudson.model.AbstractBuild.getEnvironment(AbstractBuild.java:935)
at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1036)
at hudson.scm.SCM.checkout(SCM.java:485)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1277)
at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:610)
at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:86)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:532)
at hudson.model.Run.execute(Run.java:1741)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:381)
Caused by: java.nio.file.AccessDeniedException: C:\jenkins\tools\hudson.model.JDK\Latest\bin\java.exe
at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:83)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
at sun.nio.fs.WindowsFileSystemProvider.implDelete(WindowsFileSystemProvider.java:269)
at sun.nio.fs.AbstractFileSystemProvider.delete(AbstractFileSystemProvider.java:103)
at java.nio.file.Files.delete(Files.java:1126)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at hudson.Util.deleteFile(Util.java:247)
Of course I tried everything:
Run sshd as a different (Administrator) user
Checked every error mentioned here:
https://wiki.jenkins-ci.org/display/JENKINS/SSH+slaves+and+Cygwin
here
https://wiki.jenkins-ci.org/display/JENKINS/My+software+builds+on+my+computer+but+not+on+Jenkins
and here
http://www.noah.org/ssh/cygwin-sshd.html
And nothing works. Do you have a hint where to look?
UPDATE:
Meanwhile I managed to get a bit further in the build process by deactivating the option to "Automatically install jdk" in the Jenkins settings, git clone works and gradle starts up. However, now the JAVA_HOME environment variable somehow is not accessible to the slave (although we even tried setting it in .bashrc, just to be sure). So the build fails with this message":
FAILURE: Build failed with an exception.
* Where:
Script 'http://dl.bintray.com/content/shemnon/javafx-gradle/8.1.1/javafx.plugin' line: 60
* What went wrong:
A problem occurred evaluating script.
> Could not find JavaFX Packager Tools, please set one of [jfxrtDir in Gradle Properties, JFXRT_HOME in System Environment, JAVA_HOME in System Environment, java.home in JVM properties]

For your build error after "UPDATE" I think you have to add a JDK under Manage Jenkins > Configure System > JDK or in newer versions under Manage Jenkins > Global Tool Configuration > JDK

deploy java app on Heroku launch.main error

I want to deploy a java appa on HEROKU. I am new to maven. I made all set up as per in the deploy a sample app to heroku (java+maven+ tomcat7)documentation.
and i made a bulid,It was successfull. But as soon i typed sh /target/bin/weapps i am getting the following error. Can anybody help me to sort out this issue.
Exception in thread "main" java.lang.NoClassDefFoundError: launch/Main
Caused by: java.lang.ClassNotFoundException: launch.Main</br>
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Could not find the main class: launch.Main. Program will exit.
regards,
arunbv

I had a similar problem, I (well, almost) solved it this way, just remove:
<packaging>war</packaging>
from pom.xml. I know this is not an ideal solution, but somehow the embedded tomcat plugin doesn't work with war packaging!

I don't have enough points to comment, but what article are you following? Can you link it?
Based on the error, I suspect your Main.java is not in src/main/java/launch. If you follow these instructions, I think you should be able to clear up the error:
http://devcenter.heroku.com/articles/create-a-java-web-application-using-embedded-tomcat
If that's the article you're following and you're still having trouble, it may ease the problems you're having if you simply clone the sample repo:
git clone git://github.com/heroku/devcenter-embedded-tomcat.git

Since you said you are new to maven, I think the reason of this error is that you simply put your *.java code under the root folder of the project, while you are rather expected to put it under ./src/main/java/
This should work for you. I experienced the same problem and figured this out.

This is probably dead, but in case it helps people of the future.
I was getting up and running with a java app on Heroku, using an Ubuntu machine for development - and got this same Exception in thread "main" java.lang.NoClassDefFoundError.
Double check that you're using the same java compiler version as your java sdk version.
type java -version & javac -version. Make sure they are the same version.
If not, you can fix this by reconfiguring your environment to use the same for both.
Assuming you have downloaded and installed the java version you want to use, type :
`sudo update-alternatives --config java`
You'll get a nice menu with options
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java 1061 auto mode
1 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java 1061 manual mode
2 /usr/lib/jvm/jdk1.7.0/bin/java 1
Select the version you wish to use. Done.
Now try to build.