Starting work with FXyz library - java

Have problem with adding the library to the environment, mean after i included two jar files to the project : JCSG.jar, poly2tri.jar it steal doesn't work,
do I have to do something else ?

To compile this project, I would recommend the version from https://github.com/FXyz/FXyz which comes with updated Gradle dependencies, i.e., dependencies are downloaded automatically. No need to manually download dependencies.

Related

Gradle Plugin dependency

What is the exact dependency I need to develop a Gradle Plugin in Java? Ideally I would like to get it from a well-known repository such as Maven Central or similar.
I have a Maven project with a core functionality and I just added two extra plugins, one for Ant, one for Maven. They are already tested and working; easy! Now, I wanted to add a third module for a Gradle plugin to make this functionality also available from any Gradle project.
However, I can't find the exact dependencies I need to develop a Gradle plugin.
The Gradle docs (such as https://docs.gradle.org/current/userguide/java_gradle_plugin.html) are not very well written to say the least. They mention:
the gradleAPI() dependency
or the java-gradle-plugin dependency
But they are quite unclear... no group, no version (really?).
If anyone can enlighten me to where I can get these dependencies from, I would be very thankful.
Gradle's public and internal APIs, aka gradleApi(), are bundled with the Gradle distribution and not independently published and therefore not easily consumable by Maven builds. There's the pending epic #1156 (Ensure plugin cross-version compatibility by allowing a user to depend on gradlePublicApi()) that might help here.
Since Gradle plugins are best to be built with Gradle, a pragmatic solution is to invoke the Gradle build from Maven and attach the produced artifact to the Maven build. Andres Almiray (aalmiray) once described this in the blog post Running Gradle Inside Maven (Web Archive Link). He describes the following high level steps:
Create a new Maven module (e.g. gradle-plugin) and add attach it to the parent POM
In the POM of gradle-plugin add a dependency to your core module. Use the maven-dependency-plugin to store dependencies to the Maven build folder, e.g. target/dependencies.
Create the build.gradle, add a Maven repository that points to target/dependencies (step 2) and let it depend on the core module as well as gradleApi(). Implement the Gradle plugin.
Use the exec-maven-plugin to invoke the Gradle build.
Use the maven-resources-plugin to copy the Gradle built plugin jars to the standard Maven build folder.
Use the build-helper-maven-plugin to attach the copied jars to the Maven build.
Sample project to be found here (gradle-in-maven).
https://docs.gradle.org/current/userguide/custom_plugins.html#sec:custom_plugins_standalone_project
In here it is mentioned that it is gradleApi() and I know that this works (from experience). The localGroovy() on that page is only needed if your plugin code uses groovy (does not apply if you only use groovy in the build.gradle of your plugin).
java-gradle-plugin is a library that makes it a bit simpler to make plugins, it is not required though. I personally prefer using gradleApi only.
EDIT:
It appears I've misunderstood the question. Here are the steps to get gradleApi jar:
Create a Gradle project with your desired Gradle version.
Add implementation gradleApi() dependency.
Import/run the project once.
Go to your .gradle folder (located in home folder in Linux-based operating systems).
Open caches folder
Open the version folder you want, e.g. 6.0.1
Open generated-gradle-jars folder.
Copy the jar to wherever you want and use it.
For me the 6.0.1 jar is at ~/.gradle/caches/6.0.1/generated-gradle-jars/gradle-api-6.0.1.jar
Please note that I have not tested this, I know the jar is there but I haven't tried using it.

Installing a framework without maven or gradle

I try to install Javalin framework for creating an API on my Java project. (old java 8 project without maven, gradle, etc). I would like to install the framework with adding the jars to my build path.
But If I add the main jar file then it needs another dependencies jar , then another one another one another one.. etc.
Is there any simple way to add this to my project and all it's dependencies without any build tool like Maven,etc?
I have tried adding it manually , but each jar has many dependencies that it is almost impossible(?)
Well you could create a Maven project and use it to download the dependencies for you.
Maven dependency plugin might be useful. With it you could just call:
mvn dependency:copy-dependencies
and it will download all your dependencies into target/dependency.
I don't think there's a way, I'm afraid.  Dependency management is the exact problem that build tools like Maven and Gradle were created to solve!
The framework supplier could provide a ‘fat’ jar including all the dependencies; but I'm not aware of any that do, as everyone uses Maven or Gradle (or SBT or Ivy or Grape or Leiningen or Buildr).
I think the only real alternative is to do it manually — which, as you've discovered, can be a horrible and lengthy task if the dependency tree is big.  (And would need redoing with every update.)
So I'd suggest biting the bullet and using Maven if you can.

Issues excluding transitive dependency of project reference from eclipse class path

I have several gradle projects in my eclipse workspace. For the sake of simplicity I'm only really interested in 2 of them, let's just use A and B for this.
So the problem I'm having is that Project A has an included dependency on JBoss, which pulls in javax validation-api 1.0.0.GA, and Project B has a dependency on javax validation-api 1.1.0.Final. Since Gradle itself resolves the conflict by using the newer library first, B is happy when built by gradle. But Eclipse itself includes errors which are very distracting while editing.
The correct version of the validation-api jar ends up in B's class path but the problem is that the Gradle IDE plugin changes the project(':A') dependency to a project reference, and Eclipse seems to give the project reference precedence over the external jar. So the old jar is preferred by extension.
I tried adding { exclude module: 'validation-api' } in B's build.gradle for the dependency on A which works according to the output of 'gradle dependencies', however since Eclipse just gets as far as making it a project reference, it won't exclude the jar and the problem remains.
Also per this question I tried adding { transitive = false } and the same thing happens. I don't think even the hack posed there would work for me since the .classpath contains a single reference to the Gradle container so there's nothing to remove.
I've managed to get around this by explicitly including a reference to the correct version of the jar from my gradle cache and then moving it above the Gradle Classpath Container so that eclipse sees that version first.
My question is: Is there a better/more generic way to do this? Preferably one that I can commit to source control without breaking other people's builds or requiring them to manually modify paths or properties somewhere? There is another project with what appears to be a similar issue so something I can fix in the build.gradle file would be awesome.
Worst case scenario, I could probably switch to IntelliJ if that behaves itself better than the Eclipse-Gradle integration?
These kind of transitive dependency issues are long-standing problem with Gradle Eclipse integration (both in STS tooling and also commandline generated .classpath metadata from Gradle's Eclipse plugin. The problem is the way that Eclipse computes transitive classpaths.
Only recently we found a reasonable solution to this problem. Actually there are now two solutions, one better than the other but depending on your situation you might want to use either of them.
The first solution is a bug fix that changes the classpath order of project dependencies so that they are no longer 'preferred' over jar dependencies PR-74. To get this fix you may need to install gradle tooling from a snapshot update site because the fix went in after 3.6.3.
This solution doesn't fix the real problem (you still have the 'wrong' stuff on the classpath) but just makes it less likely to cause real problem in your projects.
The second solution is to enable use of the 'Custom Tooling API model' PR-55 introduced in STS 3.6.3. This is a bit experimental and only works for recent version of Gradle, at least 1.12 but probably better to use 2.x. It also only works for projects that have 'Dependency management' enabled (if not enabled you are using the .classpath generated by Gradle's eclipse plugin which has the same 'broken' classpath issues as the STS tooling).
The 'custom tooling model' is really the better solution in principle as it fixes the way gradle classpath get mapped to eclipse projects so that project dependencies are no longer exported and each project gets its own classpath considering dependencies conflict resolution.
To enable this go to "Window >> Preferences >> Gradle" and enable checkbox "Use Custom Tooling Model".

Gradle unable to find downloaded dependency packaged as OSGi bundle (non-OSGi app)

(Edited for clarification)
My (non-OSGi) application build is in Gradle, and I am trying to upgrade from very old version of Jersey (1.1.4.1) to something much newer (1.12?). I do not pretend to know anything about using OSGi. But when I point my Gradle dependencies (with $JERSEY_VERSION set to "1.12") to:
[group: 'com.sun.jersey', name: 'jersey-server', version: "$JERSEY_VERSION"]
it downloads the jersey-server-1.12.jar into my Gradle dependencies cache under a "bundles" directory instead of the normal "jars" directory, and then Gradle seems to not include this jar in its classpath like it would if it were under a "jars" subdirectory instead.
I discovered it went under "bundles" because the POM has it labeled as an OSGi enabled jar. I do not think we are going to want to OSGi-ify our project. Am I stuck with older versions of Jersey, or is there anything else I can do to get Gradle to see the Jersey jar? I would prefer to not manually copy the file to a local repo if possible, but rather somehow depend on the dependency management capabilities of Gradle if it is up to the task.
OSGi bundles are normal jars with extra manifest entries. You should be able to use them in a non OSGi project as you would any other dependency. Is it a problem that they end up in the cache's bundles directory?
'Twas a silly oversight: moving from 1.1.4.1 to 1.12, the POM dependencies changed, so that jersey-core.jar was no longer being brought in implicitly. I had to add jersey-core.jar explicitly. I had assumed the problem was the fact that jersey-server.jar was being imported as a bundle, but I was really just getting a ClassNotFoundException for a class that was in jersey-core.jar.

Maven requires manual dependency update?

I'm new to Maven, using the m2e plugin for Eclipse. I'm still wrapping my head around Maven, but it seems like whenever I need to import a new library, like java.util.List, now I have to manually go through the hassle of finding the right repository for the jar and adding it to the dependencies in the POM. This seems like a major hassle, especially since some jars can't be found in public repositories, so they have to be uploaded into the local repository.
Am I missing something about Maven in Eclipse? Is there a way to automatically update the POM when Eclipse automatically imports a new library?
I'm trying to understand how using Maven saves time/effort...
You picked a bad example. Portions of the actual Java Library that come with the Java Standard Runtime are there regardless of Maven configuration.
With that in mind, if you wanted to add something external, say Log4j, then you would need to add a project dependency on Log4j. Maven would then take the dependency information and create a "signature" to search for, first in the local cache, and then in the external repositories.
Such a signature might look like
groupId:artifactId:version
or perhaps
groupId:artifactId:version:classifier
This identifies a maven "module" which will then be downloaded and configured into your system. Once in place it adds all of the classes within the module to your configured project.
Maven principally saves time in downloading and organizing JAR files in your build. By defining a "standard" project layout and a "standard" build order, Maven eliminates a lot of the guesswork in the "why isn't my project building" sweepstakes. Also, you can use neat commands like "mvn dependency:tree" to print out a list of all the JARs your project depends on, recursively.
Warning note: If you are using the M2E plugin and Eclipse, you may also run into problems with the plugin itself. The 1.0 version (hosted at eclipse.org) was much less friendly than the previous 0.12 version (hosted at Sonatype). You can get around this to some extent by downloading and installing the "standalone" version of Maven from apache (maven.apache.org) and running Maven from the command line. This is actually much more stable than trying to run Maven inside Eclipse (in my personal experience) and may save you some pain as you try to learn about Maven.

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