Making a Java Package in the Command Line

making a java package in the command line

packages are just directories on the filesystem.
so your package: com.mycompany.util corresponds to a directory com/mycompany/util.

When running and compiling etc your current workding directory should be where that top directory is located.

To include libraries, include them in your classpath when compiling and running. For example make a Project directory myproject and under that have your java-files and packages under myproject/src/ and libraries that you use under myproject/libs/
Then when your current workding directory is myproject execute java -cp .:libs/*.jar or the same with javac.

But I suggest you look into using ant or maven.

How do I compile my main Java program on the command line when it includes an external java package?

Your mistake is here

import org.somepackage; <--

public class MyProgram {

    public static void main(String arguments[]) {

    System.out.println("Programme up and running...");
    Human myHuman = new Human(); 
    myHuman.scream();

  }

you forgot to import class actually, you need to write this name
import org.somepackage.Human; import all package content import org.somepackage.*; or write full qualified name of class in your code

org.somepackage.Human myHuman = new org.somepackage.Human(); 
myHuman.scream();

correct mistake:

import org.somepackage.Human;

public class MyProgram {

    public static void main(String arguments[]) {

    System.out.println("Programme up and running...");
    Human myHuman = new Human(); 
    myHuman.scream();

  } 

after that compile your Human.java by this command:

javac -d classes Human.java

and MyProgram.java

javac -d classes -cp "classes" MyProgram.java

and run MyProgram by

java -cp "classes" MyProgram

Running java in package from command line

You'd run it as:

java One.Test

... but from the root directory (basic), not from the One directory. You always specify the fully-qualified class name.

Oh, and package names in Java should be lower-case, so it should be one and one.inner, not One and One.Inner. Just a convention, but one which pretty much everyone follows.

How to compile java package structures using javac

Are you sure importpackage/subpackage is in your classpath?

-cp path or -classpath path

Specify where to find user class files, and (optionally) annotation processors and source files. This class path overrides the user class path in the CLASSPATH environment variable. If neither CLASSPATH, -cp nor -classpath is specified, the user class path consists of the current directory. See Setting the Class Path for more details.

If the -sourcepath option is not specified, the user class path is also searched for source files.

If the -processorpath option is not specified, the class path is also searched for annotation processors.

http://docs.oracle.com/javase/7/docs/technotes/tools/windows/javac.html

How to build a java project using the command line?

If you are a student willing to have a Java programming career, it might help to learn how to do things from command line, e.g. edit the files, compiling the classes, testing and building the project. Oracle tutorials provide example on this matter: https://docs.oracle.com/javase/tutorial/getStarted/cupojava/win32.html#win32-2

However, I strongly advise you to embrace an IDE as your Java career will mostly reside in an IDE as real life projects are BIG! There are tons of helpful things the IDE does to you out of the box or to simplify things. Since you are a student, I will give you one basic example besides compiling: a class with 10 fields requires you some typing for getters, setters, hashCode, equals. Alternative? Few keystrokes to instruct the IDE to generate them for you. And that's one basic example.

Regarding the project structure, embracing the (since you mentioned it) Maven project structure of src/main/{java,resources}, src/test/{java,resources} even if you do NOT use Maven. This will let you forget about organizing the files around.

If you were asking about structuring the classes in the right packages, you will figure out yourself as you gain experience. Rule of thumb is to group classes together by functionality they provide. Additionally, if the packages are organized right, if you change something and touching a few classes, ideally you'd want the changed classes to be located in a single package if possible.

Learning Maven is a good choice as it is a powerful tool for building a project and keeping things organized (project structure, project dependencies, etc.).

How to import JAVA packages in cmd?

You shouldn't set the classpath using an environment variable as it is bad practice. What if you accidentally change it later for a different project and your current project breaks?

When including classes in the classpath, you can include the path of the root of the package of the class, as in the folder that contains the folders in the package structure. However, when you're including a jar in your classpath, you need to put the entire path of the jar file (relative to the current working directory) all the way up to the jarname.jar.

Also, remember that by default, java looks in the current working directory and uses that as its default classpath. However, as soon as you specify a classpath it no longer does that automatically for you. Be sure that you're including your current directory in your classpath as well.

Finally, be sure to surround the classpath in quotes otherwise java might think its a part of another argument.

I would try this:

javac -cp "./;log4j.jar" TNT.java

And then to execute the class file:

java -cp "./;log4j.jar" TNT

Hope this works, good luck!

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