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how to run kotlin class file and specify one or more library jar files?

I am looking for a way to run the standard class file as produced by Intellij for hello world, using a gradle build with kotlin-stdlib-1.3.11 as the only dependency.
I know I could make a jar file and run that but that is not the question. That question is already answered in many places, but please do not answer with those solutions as that is not the question I am asking.
The simple class file for 'hello world' needs access to the kotlin-stdlib-1.3.11.jar, and I am looking for a way to run the class file and manually specify jars to use for satisfying the dependencies.
I am making notes for team members on why:
java HelloKt
in folder where the class file is located, should give a NoClassDefFoundError and also looking to then show how manually specifying 'run the class but with the kotlin std lib as well' should then work.
I repeat, I am not trying to just get the program to run. I am trying to show how run the standard library is required to run the class file.

This is about the classpath.
The easy answer is to run kotlin instead of java, as that adds the Kotlin support to the classpath automatically:
> kotlin HelloKt
However, if you need to run java, then you'll need to set up the classpath yourself.
The manpage for java says:
The Java runtime searches for the startup class, and other classes used, in three sets of locations: the bootstrap class path, the installed extensions, and the user class path.
The first two are part of the Java installation, and rarely touched, so it's the user class path that you need to look at.
You need it to contain both kotlin-runner.jar and the path for your HelloKt.class file.  The latter could simply be . for the current directory; the former will depend where you've installed Kotlin.  (For example, I installed it using Homebrew, and that jar is currently /usr/local/Cellar/kotlin/1.3.31/libexec/lib/kotlin-runner.jar.)
The manpage continues:
-classpath classpath
-cp classpath
Specifies a list of directories, JAR archives, and ZIP archives
to search for class files. Class path entries are separated by
colons (:). Specifying -classpath or -cp overrides any setting
of the CLASSPATH environment variable.
 
If -classpath and -cp are not used and CLASSPATH is not set, the
user class path consists of the current directory (.).
So there are two ways you can do this: either set the $CLASSPATH environment variable before running java:
> export CLASSPATH="/usr/local/Cellar/kotlin/1.3.31/libexec/lib/kotlin-runner.jar:."
> java HelloKt
Or pass a -classpath or -cp flag:
> java -cp /usr/local/Cellar/kotlin/1.3.31/libexec/lib/kotlin-runner.jar:. HelloKt
(Or, as you say, you could build a jar file which includes the Kotlin support classes as well as your own.  That's probably the best option if you're going to distribute it to machines which might not have Kotlin installed.  But it's not the only option.)

As stated by #gidds, yes it is about the classpath.
The command java HelloKt is telling java the class to run is HelloKt, which is the class Kotlin uses to provide a containing class for an app called Hello, but that command does not identify where the code is that should be run. The code must be specified by the classpath. With the HelloKt.class file in the current directory, then '.' as a classpath with allow the HelloKt class to be found and the code to start, but it will quickly die because the repository 'kotlin-stdlib-1.3.11' as specified in the gradle build, must also be available to supply classes for run time. so
java -cp ".";"<path to stdlib>\kotlin-stdlib-1.3.11.jar"
will successfully run the file. Note, each jar must be a entry in the classpath, just having the folder containing the jar is not enough. On windows ';' separates entries, on mac or linux, use ':'. Each entry can be in quotes, and will need to be only if there are special characters in the path.

can't find main class java program with two jar files?

This is a pretty basic java question but I'm very new to java. I'm trying to follow this guide:
http://www.egtry.com/java/database/jdbc/hello_teradata
my jar files are located in:
tdgssconfig.jar located in /prod/user1/home/tdjar
terajdbc4.jar located in /prod/user1/home/tdjar
I created a file called tdTst.java in /prod/user1/home/tdjar dir with the script in the link above.
I than ran
java -cp ./:terajdbc4.jar tdTst.java
as well as
java -classpath terajdbc4.jar:. tdTst.java
but keep getting this error:
Error: Could not find or load main class tdTst.java
I'm new to java here so what am I doing wrong here? Do I need to point it to both jar files?

Putting the comment as a separate answer as suggested by #rkosegi
Use java -classpath terajdbc4.jar:. tdTst , without the .java

How do I know the path for Java import?

I'm trying to learn Java ( I know php ) but I don't know what path the included classes have. For example, I create a new directory in Eclipse (in the package) and drag there a class from other project. When I try to import it, it cannot find the class. Even if I don't have any dirs and the class is directly in the package, using import package.classname doesn't work...
I must be missing something but googling doesn't show me any replies.
How do I get the class path? Is it somewhere in the properties?

Java has the concept of a classpath: a path where all classes should be found.
You can get the existing classpath with this code:
System.getProperty("java.class.path")
If you run java from the command line then you have to set your own classpath with your classes.
From the classpath, use the package to find the class. For example, if the classpath is ".", which is the current folder, and you have a class called A, which is in the package com.yourcompany, then you will find the class under ./com/yourcompany/A.class
On the example you gave, go to the terminal and look for the "bin" folder and you will see all classes. However, if you want to add a new class from another project to your project, then there are simpler ways. You can simply open your build path in Eclipse and add the class from the other project onto your project.
Another way is to create a jar from the other project and add the jar to your project.

In Eclipse, go to Project->Properties-Java Build Path where you can config the classpath which allow you to import.

Mac Terminal: Could not find or load main class CLASSNAME

I am trying to run a java program through the Terminal on Mac, yet getting:
Error: Could not find or load main class (MY CLASSNAME)
I compiled this application with Eclipse, and when I run this with Eclipse, it works fine.
Furthermore, I am in the right directory, as when I type "ls" in the Terminal, it lists all the files, includes the class file I am trying to run.
This is what I type:
java mainClass
I would very much appreciate help to solve this!
Thank you,
Dean
EDIT: Solution - instead of java mainClass, it must have package too: java startPackage.mainClass

Start by making sure you are at the directory above the top level package
If the class belongs to the package com.foo.bar, you want to be in the directory above com.
In your case, you want to be in the directory above startPack.
Then you need to use the fully qualified name to run the class...
java statPack.mainClass
For example...

Make sure you have the current directory inside your CLASSPATH.
java -cp . mainClass
To set this globally, you can use export CLASSPATH=$CLASSPATH:. inside .bash_profile.
Separately, if your class lives inside a package such as com.foo.bar, then you will need to go to the parent directory of com and run your application with the full path.
java com.foo.bar.mainClass

I too faced this on Mac machine and then what I had to do to make it work was:
Problem Statement:
I had one package xyz under the root of project i.e src/main/java and then inside xyz package I had one class Student.java
my current directory is /Users/username/projectname/src/main/java/xyz:
I can see Student.java exists here
and I compiled it using javac Student.java
Now I see class file has been created at this location. But when I try to run the class file using java Student
I get the error: Error: Could not find or load main class Student
Solution:
Now the solution is to go one step back in the directory and go to root path:/Users/username/projectname/src/main/java and run the command
java xyz.Student
and it will work.
Link to follow: https://javarevisited.blogspot.com/2015/04/error-could-not-find-or-load-main-class-helloworld-java.html

For people dumb like me, make sure you are typing java HelloWorld - and NOT java HelloWorld.class - to run the compiled file with the name HelloWorld.class. This is especially so if you are used to hitting the tab key to complete the file name, as the terminal will give you java HelloWorld.class if you hit the tab key for autocomplete after typing something like java He...
This answer is here because it took 3 sites, including this answer, and 25 mintues before I figured out what I was doing wrong.
Logic is easy, typing is hard.

Using the absolute path can also resolve this problem:
java -classpath /Users/xingliu/IdeaProjects/springproject/src/main/java/ startPackage.mainClass

Can I add classes to sun's rt.jar file?

I downloaded the Javax.mail package. I have jdk1.6.0_11.
Problem is...I cannot get javac or java to find those classes!
I can get apps to compile using JCreator LE ( by adding the mail jar
to its search list ) but, when I try to run the app in a command window,
it fails.
Can I add these new classes to the rt.jar without
hurting my jdk installation?
I know java has it wired up to look there for classes.
(And, the mail classes are inside a javax package - seems like
they could reasonably be added to the javax folder in rt.jar..
Thanks!
Phil D'

No you can't, nor should you.
Instead, figure out the problem with your classloader (probably paths?). You'll need that for the next library you need to access.
Messing with rt.jar means you can't run on any other JVM.

You should either specify the jar file in your classpath: preferably on the command line with the -cp option, but possibly with the CLASSPATH environment variable.
Alternatively, you can specify its directory in the java.ext.dirs system property. For more details, see the documentation for the extensions mechanism.
You shouldn't be messing around with rt.jar. That's very definitely not the way to make extra jar files available - it's akin to trying to add Microsoft Word to the Windows kernel ;)

Adding things to rt.jar seems like a bad idea, even though its possible and easy to accomplish.
Try compile your application from the command line like this:
javac -cp <path_to_3rd_libs>/jarfile.jar . MainClass.java
If the compiler still complains about the javax.mail package try to unpack/examine the jar file to see that javax.mail package (and its expected content) is there.
(On windows its easy to examine a jar file using 7zip.)

Most definitely no.
If you post the command you are running from the command line we will be able to point you on the right direction, but most likely you are just missing a classpath parameter.
java -classpath /path/to/mail.jar MyClass

You need to understand the CLASSPATH concept which allows you to add individual classes and jar files containing classes to the "universe" of defined classes available for the code you want to compile and/or run. It is similar in idea to the PATH variable in the Windows world.
For the Windows command line this is the documentation:
http://java.sun.com/javase/6/docs/technotes/tools/windows/classpath.html
The Java Tutorial surprised me by not being well-written for this particular concept:
http://java.sun.com/docs/books/tutorial/essential/environment/paths.html
You most likely need something along the lines:
C:> set CLASSPATH=c:\javamail\first.jar;c:\javamail\second.jar
after which both java and javac should know about these classes