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Cannot run Java app on cmd using Java11 and Windows

I ahve tried several approaches as on How do I run a Java program from the command line on Windows? and create exactly the same class and packages to use the same things.
Here is the sample class located on C:\SimpleJavaProject\src\com\hello\programs:
package com.hello.programs;
public class ABC {
public static void main(String[] args) {
System.out.println("Hello world");
}
}
Then I compile it in the usual way:
C:\SimpleJavaProject\src\com\hello\programs > javac ABC.java
Later, run it by giving the package name and then my java class name:
C:\SimpleJavaProject\src > java com.hello.programs.ABC
In each time I try to run java app, I get "Error: Could not find or load main class com.hello.programs.ABC" error. Then have a look at What does “Could not find or load main class” mean? page and tried some approaches on that page. But still the same error.
It is too simple, but still I have not managed to run the simple app yet. So, how to fix this problem? And after running the app, how can I pass args on cmd?
Update: I could already generate ABC.class file by running the following command. BUT, I cannot run the app and see the "Hello world" on the console.
cd C:\SimpleJavaProject\src\com\hello\programs
javac ABC.java
--> generates ABC.class in C:\SimpleJavaProject\src\com\hello\programs

java com.hello.programs.ABC
When you run this, java is going to check each and every CLASSPATH path for that + /com/hello/programs/ABC.class, will load that, and then run it.
This must mean that either:
[A] Your classpath does not include the current directory; The fix is java -cp . com.hello.programs.ABC.
[B] you didn't do what you wrote, and e.g. dir com/hello/programs.ABC.class prints nothing.
Note that you're not doing it right; a class file should never be in a directory path that includes src. If you don't want to bother with build tools like maven or gradle, I strongly suggest you don't bother with a src dir then either. If you must, the -d option can be passed to javac to tell it where tou put the file. If you want to separate source and class files, then that should be targeting a directory named bin or build or whatnot (a sibling of the src dir).

When you use javac ABC.java you are compiling the class, and javac places it in the current directory.
So java com.hello.programs.ABC would not work (because com/hello/programs/ABC.class file does not exists).
You can use the javac -d flag:
-d <directory> Specify where to place generated class files
For instance:
> javac -d . ABC.java
> java com.hello.programs.ABC
Hello world
> cd com\hello\programs
> dir
ABC.class
Would work, because javac did place ABC in com/hello/programs.
Update: For clarity, once you compiled using javac -d . ABC.java you can run it using java com.hello.programs.ABC and you should see Hello world in the screen.

How to use javac with jars and packages

I'm trying to run java from the command line, and haven't had to include extra packages with the javac command before and I can't figure out what I'm doing wrong.
I'm running javac -d bin -cp jar1:jar2:...:jarN:PackageName MyClass.java but I'm still getting an error: package PackageName does not exist
I'm using the absolute paths for everything, and I also tried individually listing the java files inside the package but that didn't work either. I'm using a colon since I'm on a mac.
Anyone know what I am doing wrong? Thanks for any help!

I realized that I needed to compile the java files in PackageName before I could compile MyClass.java, which depended on them. So what I needed to do was: javac -d bin -cp jar1:jar2:...:jarN PackageName/*.java and then I could compile MyClass.java with bin added to the classpath as well as the jars.

what is CLASSPATH in make file

I just got a makefile like this
CLASSPATH=.:/usr/share/java/antlr.jar
Mipsim.class: Mipsim.java MipsimLexer.class MipsimLexerTokenTypes.class MipsimParser.class Memory.class Processor.class
javac -classpath .:/usr/share/java/antlr.jar Mipsim.java
Memory.class: Memory.java MemoryAccessible.class
javac Memory.java
Processor.class: Processor.java
javac Processor.java
MemoryAccessible.class: MemoryAccessible.java
javac MemoryAccessible.java
MipsimLexer.java MipsimLexerTokenTypes.java MipsimParser.java: Mipsim.g
antlr Mipsim.g
MipsimLexerTokenTypes.class: MipsimLexerTokenTypes.java
javac MipsimLexerTokenTypes.java
MipsimLexer.class: MipsimLexer.java
javac MipsimLexer.java
MipsimParser.class: MipsimParser.java
javac MipsimParser.java
clean:
rm -f *.class MipsimLexer.* MipsimLexerTokenTypes.* MipsimParser.*
I have to run this make file, and build the object code.
However, the terminal told this
antlr Mipsim.g
make: antlr: No such file or directory
make: *** [MipsimLexer.java] Error 1
I guess probably anrlr.jar couldn't be found in this case. So I just changed the CLASSPATH into
CLASSPATH=.:/antlr.jar
and put antlr.jar in the same folder, then tried it again. The same error just happened again.....
Could somebody please help me out?
Thanks

CLASSPATH=.:/antlr.jar
That's not going to work. It says to use the current directory and the antlr.jar file in the root file system (which probably won't exist).
You may want to try:
CLASSPATH=.:./antlr.jar
And make sure that it exists for the duration of the antlr executable. Some make programs will execute each command in a separate shell so changing the CLASSPATH may not carry forward. I tend to use the bash "set variable for one process" method:
CLASSPATH=.:./antlr.jar antlr Mipsim.g
On top of that, the way you generally run antlr is by running java, giving the class you want to run, with something like:
java -cp ./antlr.jar org.antlr.Tool Mipsim.g
If you have an executable file (or script) antlr which will do that for you, it appears not to be in your path.

How do I compile my Java source files?

My source files are in this folder: c:\data\mycompany.
All of my source files contain the following as the first line: package mycompany; Now from the c:\data folder, I compiled everything using this command: javac mycompany/*.java -extdirs c:\some\other\folder\with\libs. This compiles fine. Now when I try to execute it (again from c:\data) using this command: java mycompany/test then i get this error:
Exception in thread "main"
java.lang.NoClassDefFoundError:
mycompany/test Caused by:
java.lang.ClassNotFoundException:
mycompany.test at java.net.URLClassLoader$1.run(Unknown Source)
I also tried the below command but it reproduces the same error:
java mycompany/test -extdirs c:\some\other\folder\with\libs
Is this the proper way to compile/run?
Here is my source-code:
package MyCompany;
public class Test
{
public static void main(String[] args)
{
System.out.println("test");
}
}

You need to set the classpath. See for example this SO question.

You shouldn't be using extdirs when invoking java, you should be setting your classpath with -cp
By the way, when invoking a main java class, you should provide the class name, not the path to the class, hence, it's likely mycompany.test (if your class that contains main is named test), not mycompany/test. It's not an error as Java fixes it for you.

that is saying that the .class files are not on the classpath how you are compiling should be fine, you need to add the directory with the resulting .class files to your classpath when you try and run your test code.
java -cp <path to classes> classtorun
so your example might look like
java -cp <path to classes>;<path to libs> mycompany.Test
you should really look at ANT to automate your compile and build to an executable .jar file. Nobody does this fiddly stuff by hand because of all the repetitive typing and chances for errors. ANT was created to avoid all this minutia and let you concentrate on solving coding problems and not struggling with the command line tools. Read this.

Try this to compile:
mkdir classes
javac -d classes *.java
Only create the /classes directory the first time. The -d directory tells javac to put your .class file under /classes.
To run, do this:
java -cp .;classes MyCompany.Test
This should work fine.

compiling java from the command line

I have a package called studentServer which contains two sub packages student and common.
The common folder has references to the student package and i would like to be able to compile this. How could i do this?
javac student\*.java - compiles the student package
but when i try something similar with the common package errors are thrown - I understand it's something to do with the classpath
javac -verbose -classpath "\student" common\*.java
But I couldn't get this working. Any help would be great.
http://pastebin.com/m2a2f5d5d - here's the output from the compiler

This is a bit vague, but I suspect the classpath for the student code is wrong. Try without the leading backslash.

If you have a directory structure
source/
studentServer/
student/
common/
classes/
And you're in the directory above source, then you want to set the source path to 'source' with the -sourcepath option. You probably also want to use the -d option to tell javac where to put the compiled classes, so they aren't all mixed up with the source:
java -d classes -sourcepath source source/studentServer/student/*.java source/studentServer/common/*.java

go like this
c:\>
use change directory command cd until you get the desired directory
(ex: c:\javaEx\proj1\)
now
cd javaEx go like this
c:\javaEx\proj1\javac *.java
now compilation done in all java files in the proj1 directory.