How to add a dependency to module path?

I am very new to programming, and while working on my first software development project I came across the error: "package javax.activation is not visible." I have read other posts that have said that in order to fix the error, one must add a dependency to the module path?

Because I'm just starting out, I really don't know what this means and how to go about that, and was wondering if someone could point me in the right direction? Thanks in advance. (I'm also using JGrasp if that matters)

Solution

Broadly speaking, a dependency is code (often written by someone else) which your application needs to compile.

A dependency in your case, is a java library which has classes that need to be on your class path. You can find more about class paths here: https://docs.oracle.com/javase/tutorial/essential/environment/paths.html. In order to overcome error mentioned in a question, you need to have javax.activation module dependency on your class path.

You could do it in few ways. In the majority of IDEs (in your case we are talking about JGrasp) there is a way to add a dependency to the project directly. Then, your IDE would compile the code with given dependency on a class path and problem would be solved. And that would be the first and most beginner-friendly way, unfortunately I haven't a faintest idea about JGrasp so I'm going to focus on other solutions.

The second way you could do this is to build your program with build automation tool, such as Apache Maven or Gradle. You should definitely check those guys out, as they are insanely useful when it comes to building Java code and, sooner or later, you will probably start using them anyway. Let's say you have chosen Apache Maven. In your project you would then have a pom.xml file and you would simply look-up the needed dependency in Maven Central repository, add it to your dependencies section in pom.xml file and build the application. Your pom would look something like this:

  <project>
        ...
        <dependencies>
    <!-- https://mvnrepository.com/artifact/javax.validation/validation-api -->
    <dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>2.0.1.Final</version>
    </dependency>
    </dependencies>
    ...
    </project>

Of course Apache Maven is not a lightweight tool so you would have to take some time to learn how to build code with it. I recommend starting with this tutorial: https://maven.apache.org/guides/getting-started/maven-in-five-minutes.html I also encourage you to get your hands on Apache Maven docs, as it is quite readable and transparent.

And the last way I can think of is to manually compile your application and include the required dependency during the compilation process. There are plenty of tutorials on SO that tell you how to do this, so I'll simply summarize and indicate the resources. What you need to do is to find the required dependency jar package. You will want to search the maven central repository (see: https://mvnrepository.com/) and from there download your .jar file. The next thing you need to do is to learn how to compile your Java code to .class files including the downloaded jar. To acquire such a wonderful skill, please see this one: How to include jar files with java file and compile in command prompt

Amongst those three ways, the recommended one is to get to know with build tools such as Apache Maven or Gradle. Hope I helped you! Good luck