How to make a gradle project depend on another gradle project - java

I am developing two gradle projects, project A and project B. Project A is dependent on project B. I want to add project B into the dependencies of project A, like adding a dependency from maven central.
I could compile project B into a fat jar and add the jar file into the dependencies of project A, but there is a problem: the dependencies of project A and project B conflicted.
For example, there is compile group: 'com.google.code.gson', name: 'gson', version: '2.8.5' in both projects.

I could compile project B into a fat jar and add the jar file into the dependencies of project A
No, never do that, of course it will trigger dependencies issues. ProjectA has no way to determine if a dependency is a duplicate in a fat jar. Gradle has a built-in way to handle it.
project(':projectA') {
dependencies {
compile project(':projectB')
 }
}

Related

Gradle dependencies: package does not exist

I know this has been asked multiple times but the questions have multiple answers.
I'm trying to use a Java package that's a dependency of my dependency. Let's say I've built this gradle project called "ee_tools". And that has a dependency called "my_models", which has a package called "com.mycompany.my_models.db". So in the ee_tools project build.gradle, I've got
dependencies {
// My stuff
implementation group: "com.mycompany", name: "my_models", version: "1.0.0"
}
Then in my current project, I've got
dependencies {
// My stuff
implementation group: "com.mycompany", name: "ee_tools", version: "1.0.0"
Shouldn't this mean that the public classes in my_models are accessible through ee_tools to my current project? Gradle was able to find both in my artifactory instance. And the gradle dependencies command shows ee_tools under the compileClasspath, implementation, and testCompileClasspath trees, but not with its children dependencies. It also shows up in the runtimeClasspath and testRuntimeClasspath trees with its children dependencies, including my_models.
I am also able to see that package inside the jar on the left side of IntelliJ, under the "External Libraries" tree, along with some classes.
But when I try to use the my_models package in my current project, IntelliJ can't find it and it fails a gradle build with the error
error: package com.company.my_models.db does not exist
It can't find any package in that dependency. What gives? Am I declaring the dependencies incorrectly? Or is this a gap between the gradle binary in my command line vs IntellJ and gradlew?
If ee_tools depends on my_models, then your gradle file in ee_tools should be like
implementation project(path: ":path:to:my_models", configuration: 'default')
:path:to:my_models is defined in settings.gradle in project root path like this:
include ':path:to:my_models'

Why gradle removes dependency when I build a project

I have no idea why gradle is doing this to me. I have a multiproject that looks like this:
|Parent
|client
|common
|service
Parent is just an empty project and client, common and service are gradle java projects:
I have some classes that are used in both client and service, therefore I wanted to create a common project and build a jar that I would later use in both service and client. I can build the common jar, but whenever i try to do 'add dependency on common' and then try to 'refresh gradle', it removes the dependency and fails to build!
This is what I do:
Then I press this because I want to build it:
And it just removes the dependency!!!
This is build.gradle file from client project:
plugins {
id 'org.springframework.boot' version '2.2.5.RELEASE'
id 'io.spring.dependency-management' version '1.0.9.RELEASE'
id 'java'
}
group = 'sot.rest'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
repositories {
mavenCentral()
}
dependencies {
compile group: 'org.springframework', name: 'spring-web', version: '5.2.4.RELEASE'
implementation 'org.springframework.boot:spring-boot-starter'
// https://mvnrepository.com/artifact/com.google.code.gson/gson
compile group: 'com.google.code.gson', name: 'gson', version: '2.8.6'
}
Please help, Im desperate!!
Check out my answer on your previous question. It should give you an idea how to structure and declare the multi-module gradle projects.
I think that when you add the dependency on module with IntelliJ, it just adds it to the project structure through project settings in IntelliJ. And later, when you hit refresh, IntelliJ configures the project based on Gradle files.
To make it working, the Parent project should also be a Gradle project. If it isn't just add build.gradle and settings.gradle under the Parent directory.
Then in settings.gradle add the subprojects like:
rootProject.name = 'Parend'
include('common') //this adds the module
include('client')
include('service')
And later, in build.gradle files of client and service modules add the common module as dependency with:
dependencies {
implementation project(':common')
//...
}
If you are going to work more with Gradle, you could take a look at this article about overall insight on Gradle.
Edit:
(I understood that when you use implementation it doesn't throw errors)
To work with multimodule project with Gradle, the root project also needs to be a Gradle project. The root might or might not contain any source code, but it needs to have its own Gradle files.
So if your project structure needs to be like:
Root project 'parent'
+--- Project ':client'
+--- Project ':common'
\--- Project ':service'
Then the parent and submodule projects need to be set as Gradle projects.
To make it the parent project needs to have at least a settings.gradle file and declared includes for submodules, similarly to:
rootProject.name = 'parent'
include 'common'
include 'client'
include 'service'
Each of modules (client,common,service) must have a build.gradle files under its directory. Submodules using common, so the service and client must add the common as dependency in their own build.gradle files, like:
dependencies {
implementation project(':common')
//and rest of required dependencies
//testCompile group: 'junit', name: 'junit', version: '4.12'
}
Then you should be able to import public classes from common in those submodules and rebuild or reimport project without error.
Since the parent project doesn't contain any source code, then it doesn't need its own build script, but then build file of all of the submodules needs to declare the java plugin on top of the build file:
plugins {
id 'java'
}
Since you are working with IntelliJ and your project could have different structure previously, then the project structure in IntelliJ setting could be messed up now.
To fix it you could go to File->Project Structure->Modules and remove/reimport the parent module again.
If you don't have many classes now, I'd recommend you to create a new project. In the "New Project" window pick Gradle and uncheck Java in "Additional Libraries and Frameworks". This will create blank Gradle project.
After the project is generated, do a right mouse click on parent, and select New->Module. In new module window again pick Gradle and leave the Java checked (since the submodules will contain source code).
With that, the IntelliJ will automatically include created module to the settings.gradle file of root/parent project and the build file of that module will contain the basic configuration (e.g. the java plugin).
But you still add the dependency of one module in another in the build.gradle file of that module.

Including local jar dependency with corresponding source jar in gradle

How can I include a local jar dependency and its corresponding sources jar (for my IDE, Intellij) in Gradle?
I have tried adding a flatDir to lib (a directory in the same parent directory as all the Gradle stuff) under repositories, where lib contains mylib-1.0.jar and mylib-1.0-sources.jar. I then put implementation name: "mylib-1.0" under dependencies. The jar with compiled classes was included, but not the sources.
I also tried creating a local maven repository. In this case, lib contained
lib/xxx/yyy/mylib/1.0/mylib-1.0.jar
and
lib/xxx/yyy/mylib/1.0/mylib-1.0-sources.jar
where xxx.yyy is the group ID. I added
maven {
url uri("lib")
}
under repositories and
implementation group: "xxx.yyy", name: "mylib", version: "1.0"
under dependencies. Still did not work--neither jars were included this time.
I also tried adding a minimal POM in the same directory as both the jars, but that did not change anything.
Any idea as to where I could be going wrong?
Note: I am no expert at using Gradle or Maven.
Edit: Rationale: in case somebody suggests it, I am aware I can just include as a dependency the jar with the compiled class and "link" the sources jar to it in Intellij, but then every time I refresh gradle I have to re-link them.
I provide below the following approaches.
Prior to gradle 5
dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
}
Here libs is the directory which contains the list of jar files and it should be location inside your project base directory.
You can also use in the following manner if you have only one jar file. Here libs refer to the directory which contains only one jar file and libs is available in the project base directory.
dependencies {
compile files('libs/your jar file name.jar')
}
If you want to specify a list of jar files, you can use in the following manner.
dependencies {
compile files(‘libs/a.jar’,
‘libs/b.jar’,
‘libs/c.jar’
)
}
In Gradle 5
You have to use in the follwong manner.
dependencies {
externalLibs files('libs/a.jar', 'libs/b.jar')
}

how to exclude test dependences in gradle

first, I have a project like this:
project-a
src
main
java
A.java
test
java
ATest.java
then, I have another project like this:
project-b
src
main
java
B.java
test
java
BTest.java
the build.gradle configuration, project-b dependence project-a
dependencies{
compile project(":project-a")
}
the question is BTest.java can access ATest.java, how to avoid this?
-------------------show more detail---------------
settings.gradle
rootProject.name = 'test-dependence'
include 'project-a', 'project-b'
project-b/build.gradle
dependencies {
compile project(":project-a")
testCompile group: 'junit', name: 'junit', version: '4.12'
}
Unfortunately there's a bit of an impedence mismatch between Gradle modules and IntelliJ modules since Gradle allows multiple classpaths (configurations) in a module and IntelliJ has a single classpath per module.
Basically IntelliJ will allow BTest.java to access ATest.java but if you built from command line, Gradle won't allow it.
Try the following in intellij Gradle Settings.
Preferences -> Build, Execution, Deployment -> Build Tools -> Gradle: check create separate modules per source set
Related question here

Gradle dependencies of local dependency

So let's say I have project A, which requires certain dependencies. And I have project B, which has project A as one of its dependencies. So I have the following code in project B's build.gradle:
project B's build.gradle:
dependencies {
compile files("projectA_dir/build/libs/projectA.jar")
}
However, since Gradle does not include project A's dependencies in projectA.jar by default. I was wondering if there's a way to let project B successfully compile project A without creating a fatjar for project A.
The jar file doesn't contain the transitive dependencies and doesn't have a pom file which describes the dependencies used by the module.
It means that, if you are importing a jar file using compile files you have to specify the dependencies also in your project.
You should use a maven repository, private or public, to avoid the issue.
In this case, gradle downloads the dependencies using the pom file which will contains the dependencies list.

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