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Problem with java classpath when executing jar

I am trying to execute a java application, which is packaged as jar archive.
java -cp .\lib\json.jar -jar ".\myarchive.jar"
I get an error saying that the classes inside my json.jar archive cannot be found.
Exception in thread "main" java.lang.NoClassDefFoundError: json/serializers/JsonTypeResolversInstance
Caused by: java.lang.ClassNotFoundException: json.serializers.JsonTypeResolversInstance
at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 2 more
The jar file contains the class, so i think this error should not happen. When executing the code using my IDE it runs without errors.
I have tried to fix this in many ways, without success.

Using the -cp and -jar options at the same time does not work. When you use the -jar option, then the -cp option is ignored.
There are two ways to run code in a JAR file in Java.
First way: Use the -cp option and specify the name of the class that contains the main method on the command line. For example:
java -cp .\lib\json.jar;.\myarchive.jar com.mypackage.MyMainClass
When you do it like this, you specify the classpath on the command line (using -cp). The classpath must contain all JAR files and/or directories that contain all the classes that the application needs. You must also specify the name of the class to run on the command line.
Also, when you do it like this, the manifest file that might be present in the JAR file is ignored.
Second way: Use the -jar option. For example:
java -jar .\myarchive.jar
When you do it like this, then Java will look at the manifest file in the JAR file. The classpath and the name of the class to run will be taken from the manifest file, and the -cp option on the command line will be ignored.
For details see the documentation of the java command.

Unable to compile using Picocli

I'm a dev student
I would love to use Picocli in my project, unfortunately I doesn't understand how to compile using Picocli
I trie to follow the instruction given here https://picocli.info/ or here https://picocli.info/quick-guide.html but the step to compile aren't detailed. I'm not using Gradle nor Maven but they aren't really listed as required.
This is how it tried to compile the Checksum example given in the picocli.info webpage :
jar cf checksum.jar Checksum.java ; jar cf picocli-4.6.1.jar CommandLine.java && echo "hello" > hello
Then I simply copy paste this gived command : https://picocli.info/#_running_the_application
java -cp "picocli-4.6.1.jar:checksum.jar" CheckSum --algorithm SHA-1 hello
And get the following result :
Error: Could not find or load main class CheckSum
Caused by: java.lang.ClassNotFoundException: CheckSum
I tried to compile everything myself and then add the .jar like this :
java CheckSum -jar picocli-4.6.1.jar
But then the error output looks like this:
Exception in thread "main" java.lang.NoClassDefFoundError: picocli/CommandLine
at CheckSum.main(Checksum.java:33)
Caused by: java.lang.ClassNotFoundException: picocli.CommandLine
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:521)
... 1 more
Witch I don't understand since I added the dependency.
What am I missing ?
Thanks in advance

The problem is that the command jar cf checksum.jar Checksum.java only creates a jar file (jar files are very similar to zip files) that contains the Checksum.java source file.
What you want to do instead is compile the source code first. After that, we can put the resulting Checksum.class file (note the .class extension instead of the .java extension) in the checksum.jar. The Java SDK includes the javac tool that can be used to compile the source code. Detailed steps follow below.
First, open a terminal window and navigate to a directory that contains both the Checksum.java source file and the picocli-4.6.1.jar library.
Now, the command to compile (on Windows) is:
javac -cp .;picocli-4.6.1.jar Checksum.java
Linux uses : as path separator instead of ;, so on Linux, the command to compile is:
javac -cp .:picocli-4.6.1.jar Checksum.java
The -cp option allows you to specify the classpath, which should contain the directories and jar/zip files containing any other class files that your project uses/depends on. Since Checksum.java uses the picocli classes, we put the picocli jar in the classpath. Also add the current directory . to the classpath when the current directory contains any classes. I just add . habitually now.
Now, if you list the files in the current directory, you should see that a file Checksum.class has been created in this directory.
Our Checksum class has a main method, so we can now run the program with the java tool:
On Windows:
java -cp .;picocli-4.6.1.jar Checksum
On Linux:
java -cp .:picocli-4.6.1.jar Checksum
Note that when running the program with java you specify the class name Checksum, not the file name Checksum.class.
You can pass arguments to the Checksum program by passing them on the command line immediately following the class name:
java -cp .:picocli-4.6.1.jar Checksum --algorithm=SHA-1 /path/to/hello
When your project grows, you may want to keep the source code and the compiled class files in separate directories. The javac compile utility has a -d option where you can specify the destination for the compiled class files. For example:
javac -cp picocli-4.6.1.jar:otherlib.jar -d /destination/path /path/to/source/*.java
This should generate .class files for the specified source files in the specified destination directory (/destination/path in the example above).
When you have many class files, you may want to bundle them in a single jar file. You can use the jar command for that. I often use the options -v (verbose) -c (create) -f (jar file name) when creating a jar for the compiled class files. For example:
jar -cvf MyJar.jar /destination/path/*.class /destination/path2/*.class
Enjoy!

Why exec-maven-plugin fails while java console command works?

This problem has arisen while working with the Java Chromium Embedded Framework (JCEF).
The JCEF uses a native SO library (libcef.so) and a SO library for the JNI bindings (libjcef.so). I believe the embedded Chromium looks for a file named icudtl.dat next to it, i.e. in the same directory that the libraries reside.
For the following explanation, asume that all those required files are in the same directory, named jcef_libs.
I wrote a test application using JCEF. After compiling, if I execute it with the java command, i.e.
$ export LD_LIBRARY_PATH=/path/to/jcef_libs
$ java -cp src/main/java:/path/to/maven/repo/jcef.jar:/path/to/maven/repo/jogl-all/2.2.4/*:/path/to/maven/repo/gluegen-rt/2.2.4/* tests.simple.MainFrame
it works flawlessly.
On the other hand, using the exec-maven-plugin raises a fatal error, due to not finding the named icudtl.dat file. The POM file is configured to use exactly the same artifacts as the java command does.
$ mvn exec:java -Dexec.mainClass="tests.simple.MainFrame"
[1201/123038:FATAL:content_main_runner.cc(721)] Check failed: base::i18n::InitializeICU().
I have tested the java command with the icudtl.dat file removed from the jcef_libs directory, experiencing the same error, i.e. the error raises only when the icudtl.dat is not found.
Any help will be appreciated.
UPDATE
I have been tracing what maven does under the hood. The failing mvn command above executes this internally:
java -classpath /usr/share/maven2/boot/classworlds.jar -Dclassworlds.conf=/usr/share/maven2/bin/m2.conf -Dmaven.home=/usr/share/maven2 org.codehaus.classworlds.Launcher "exec:java" "-Dexec.mainClass=tests.simple.MainFrame"
I.e. it executes my test application through a launcher. I don't know where this launcher is going to execute my application but, again, I need the icudtl.dat in that directory.
Any idea how could I workaround this?

Running Rake Tasks In WAS without JRuby

Related to : Executing rake tasks on an exploded war on tomcat without jruby being installed
I'm trying to run rake tasks in my Tomcat server that doesn't have JRuby installed. I'm using warbler to create a war file.
Using the answer to the linked question, I ran:
java -cp lib/jruby-core*.jar:lib/jruby-stdlib*.jar org.jruby.Main -S rake -T
This gets me the error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/jruby/Main
Caused by: java.lang.ClassNotFoundException: org.jruby.Main
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
ls lib gets me:
ems-gems-activerecord-jdbc-adapter-1.2.2-lib-arjdbc-jdbc-adapter_java.jar
gems-gems-jdbc-sqlite3-3.7.2-lib-sqlite-jdbc-3.7.2.jar
gems-gems-jruby-jars-1.6.8-lib-jruby-core-1.6.8.jar
gems-gems-jruby-jars-1.6.8-lib-jruby-stdlib-1.6.8.jar
gems-gems-jruby-rack-1.1.10-lib-jruby-rack-1.1.10.jar
gems-gems-json-1.7.5-java-lib-json-ext-generator.jar
gems-gems-json-1.7.5-java-lib-json-ext-parser.jar
gems-gems-therubyrhino_jar-1.7.4-jar-rhino-1.7R4.jar
gems-gems-warbler-1.3.6-lib-warbler_jar.jar
jruby-core-1.6.8.jar
jruby-rack-1.1.10.jar
jruby-stdlib-1.6.8.jar
ojdbc6.jar
Opening up the jruby-core-1.6.8.jar file, I can see that there is indeed a org/jruby/Main.class file.
As one can see from the file listing, there is no jruby-complete jar file, so I can't run the command from https://stackoverflow.com/a/9982556/684934
What am I doing wrong, and is there by now a better way to do this?

I was working on a similar problem 2 months ago, so things may have changed, but I needed to include all the jars in my class path, had to use bin stubs, and had to set GEM_HOME to get everything working. It may have been simpler, but the posts you referenced didn't work for me either.
I actually had jruby installed, (but I was only using it to build the concatenated class path), so my setup was something like:
cd /path/to/application/
export GEM_HOME=/path/to/application/gems
export CLASSPATH=$(jruby -e 'puts Dir["lib/*.jar"].join(":")')
RAILS_ENV=production java -cp $CLASSPATH org.jruby.Main bin/rake -T
Also useful, the jruby-jars gem can be included in your gemfile to set the version of jruby that warbler includes (I was using gem 'jruby-jars', '1.7.0.preview2' as 1.7.0 wasn't released yet)

How to run Java program in terminal with external library JAR

This should be simple but I have never done it before and didn't find any solution.
I am currently using Eclipse to code my program, which imports some external JAR library such as google data api library. I can use Eclipse to compile/build/run the program.
But now I want to run it in terminal, so where should I put those JAR files, and how to build and run the program?
Thanks!

You can do :
1) javac -cp /path/to/jar/file Myprogram.java
2) java -cp .:/path/to/jar/file Myprogram
So, lets suppose your current working directory in terminal is src/Report/
javac -cp src/external/myfile.jar Reporter.java
java -cp .:src/external/myfile.jar Reporter
Take a look here to setup Classpath

For compiling the java file having dependency on a jar
javac -cp path_of_the_jar/jarName.jar className.java
For executing the class file
java -cp .;path_of_the_jar/jarName.jar className

you can set your classpath in the in the environment variabl CLASSPATH.
in linux, you can add like
CLASSPATH=.:/full/path/to/the/Jars, for example ..........src/external
and just run in side ......src/Report/
Javac Reporter.java
java Reporter
Similarily, you can set it in windows environment variables.
for example, in Win7
Right click Start-->Computer
then Properties-->Advanced System Setting --> Advanced -->Environment Variables
in the user variables, click classPath, and Edit and add the full path of jars at the end.
voila

Suppose your jar application "myapp.jar" has the following code snippet written inside it.
import org.json.JSONObject;
public class Main {
public static void main(String[] args) {
// write your code here
System.out.println("Hello World!");
JSONObject jo = new JSONObject("{ \"abc\" : \"def\" }");
System.out.println(jo.toString());
}
}
It is using the external library json.jar from which we imported "org.json.JSONObject".
Running the following command will result in an error.
java -jar myapp.jar
Exception message:
Exception in thread "main" java.lang.NoClassDefFoundError: org/json/JSONObject at com.reve.Main.main(Main.java:10)
Caused by: java.lang.ClassNotFoundException: org.json.JSONObject at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(Unknown Source) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(Unknown Source) at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
... 1 more
We must include the json.jar file while running the jar file. We have to specify the class path of the file before building our myapp.jar file.
Inside META-INF/MANIFEST.MF file:
Manifest-Version: 1.0
Class-Path: lib/json.jar lib/example2.jar
Main-Class: com.reve.Main
Specify the external libraries separated by spaces under the Class-Path keyword. Then after building the project and the artifact, we can run the jar file by simply writing the same command we discussed above.