# Accessing build.graddle information from a .java file?

**URL:** <https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756>\
**Category:** Help/Discuss\
**Created:** [December 8, 2016, 5:46pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756 "2016-12-08T17:46:08Z")\
**Posts on this page:** 12\
**Page:** 1

<div class="post-metadata">

**Author:** ![therock](https://avatars.discourse-cdn.com/v4/letter/t/ac8455/32.png) [@therock](https://discuss.gradle.org/u/therock)\
**Post date:** [December 8, 2016, 5:46pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/1 "2016-12-08T17:46:09Z")

</div>

So, let me preface by saying my understanding of gradle is near to non-existent.

I’m running unit tests and I was trying to access some information from my gradle file.

I.e: I have version ‘1.0’ and I want to run a test that verifies the version of my unit test tool to the application. However, I have no idea on how to retrieve that specific thing. I don’t need straight up code but just a pointer in the right direction seeing as I’m completely lost as the moment.

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<div class="post-metadata">

**Author:** ![Lance\_Java](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/lance_java/32/787_2.png) [@Lance\_Java](https://discuss.gradle.org/u/Lance_Java)\
**Post date:** [December 8, 2016, 11:25pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/2 "2016-12-08T23:25:33Z")

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1. generate a property file in a gradle task
2. wire the task into the DAG before the test task
3. add the generated folder to the testRuntime classpath
4. lookup the property file from the classpath in your tests

See [here](https://github.com/uklance/gradle-maven-share/blob/master/build.gradle#L33) where I dynamically create files in the `$buildDir/testkit` folder which is added to the `testRuntime` classpath

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<div class="post-metadata">

**Author:** ![Lance\_Java](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/lance_java/32/787_2.png) [@Lance\_Java](https://discuss.gradle.org/u/Lance_Java)\
**Post date:** [December 9, 2016, 10:20am UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/3 "2016-12-09T10:20:04Z")

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Another option is to set the [systemProperties](https://docs.gradle.org/current/dsl/org.gradle.api.tasks.testing.Test.html#org.gradle.api.tasks.testing.Test:systemProperties) of the test task. I dislike this approach because it makes it more difficult to run the test via eclipse/junit since either gradle needs to run the test or you need to set the system property in the junit run target.

With the classpath / property file based approach I can run in eclipse using right click, run as junit test (after an initial gradle build creates the file)

Note: You can right click, run as gradle test for either solution. I just prefer the junit runner (quicker, prettier output)

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<div class="post-metadata">

**Author:** ![therock](https://avatars.discourse-cdn.com/v4/letter/t/ac8455/32.png) [@therock](https://discuss.gradle.org/u/therock)\
**Post date:** [December 9, 2016, 2:34pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/4 "2016-12-09T14:34:27Z")

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Mhm, the thing I was wondering is that, in the event that I dynamically create the file, there’s the issue of pointing to it no? (I may be completely wrong here ) I was seeing it this way: I have a test in src/test/java/tests package. Now, if in that tests package I have a file test1.java with the following declaration:

versionOfThisApp = “path to dynamically created file”

Doesn’t this create a compilation problem? Because the file won’t exist at compile time but only at run time no?

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<div class="post-metadata">

**Author:** ![Lance\_Java](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/lance_java/32/787_2.png) [@Lance\_Java](https://discuss.gradle.org/u/Lance_Java)\
**Post date:** [December 9, 2016, 2:56pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/5 "2016-12-09T14:56:50Z")

</div>

In your test just use

```gradle
InputStream in = getClass().getClassLoader().getResourceAsStream("generated-file.properties");
Properties props = new Properties();
props.load(in);
String version = props.get("version") 

```

There’s no compilation issue… The filename is a string?

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<div class="post-metadata">

**Author:** ![therock](https://avatars.discourse-cdn.com/v4/letter/t/ac8455/32.png) [@therock](https://discuss.gradle.org/u/therock)\
**Post date:** [December 9, 2016, 3:12pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/6 "2016-12-09T15:12:56Z")

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Ah, I’ll try it out then. I was thinking of pointing to a static variable that’s why. using file IO makes much more sense now. Thank you!

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<div class="post-metadata">

**Author:** ![Lance\_Java](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/lance_java/32/787_2.png) [@Lance\_Java](https://discuss.gradle.org/u/Lance_Java)\
**Post date:** [December 9, 2016, 3:38pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/7 "2016-12-09T15:38:18Z")

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That’s also an option. You could generate a `.java` file and add the folder to the test sources

```gradle
sourceSets.test.java {
   srcDir "$buildDir/generated" 
} 

```

Your generation task would need to be wired into the DAG before the “compileTestJava” task

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<div class="post-metadata">

**Author:** ![therock](https://avatars.discourse-cdn.com/v4/letter/t/ac8455/32.png) [@therock](https://discuss.gradle.org/u/therock)\
**Post date:** [December 9, 2016, 3:45pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/8 "2016-12-09T15:45:24Z")

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Mhm, thing is I’ve tried ( i think) by doing this way ( an answer you gave in the past)

```
   task generateSources {
outputDir = file("$buildDir/version")
outputs.dir outputDir
doFirst {
    def srcFile = new File(outputDir, "com/foo/Version.java")
    srcFile.parentFile.mkdirs()
    srcFile.write("""
    package com.foo;
                   public class Version {
                 public static String getVersion() { return "$project.version"; }
                }
           """)
      }
}
compileJava.dependsOn generateSources
compileJava.source generateSources.outputs.files, sourceSets.main.java

```

Of course I tried this changing the paths and all that  
And, I get a bunch of errors because IntelliJ 1)cannot resolve outputs ( or inputs) and the new File call gives me an “Constructor call is ambiguous”

I’ve also tried using

`processResources { expand ( project.version) }`

into a version.properties file which contained

```
   version=%APP_VERSION_TOKEN%

```

but all that returns is %APP\_VERSION\_TOKEN%.  
Could that be because of my file structure where I don’t have a main ( i only have src/test/java/tests package ) - though I doubt that affects the tests at all  
Unfortunately I’m taking over this tool for someone but my understanding of gradle is near to none, so I’m going by searching even though this is more advance than beginner tasks.

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<div class="post-metadata">

**Author:** ![Lance\_Java](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/lance_java/32/787_2.png) [@Lance\_Java](https://discuss.gradle.org/u/Lance_Java)\
**Post date:** [December 9, 2016, 4:47pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/9 "2016-12-09T16:47:47Z")

</div>

You’ll want to add the sourceDir to the `sourceSets` model rather than tweaking the `compileJava` task directly.

Do this

build.gradle

```gradle
apply plugin: 'java' 
repositories {
   ... 
} 
dependencies {
   testCompile 'junit:junit:4.12'
}
task generateTestSources {
	inputs.property "version", project.version
	outputs.dir "$buildDir/generated"
	doFirst {
		def versionFile = file("$buildDir/generated/foo/Version.java")
		versionFile.parentFile.mkdirs()
		versionFile.text = 
"""
package foo;

public class Version {
	public static String getVersion() {
		return "$project.version";
	}
}
"""
	}
}

compileTestJava.dependsOn generateTestSources

sourceSets.test.java {
	srcDir "$buildDir/generated"
}

```

src/test/java/foo/VersionTest.java

```gradle
package foo;

import org.junit.*;

public class VersionTest {
	@Test
	public void testVersion() {
		Assert.assertEquals("unspecified", Version.getVersion());
	}
}

```

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<div class="post-metadata">

**Author:** ![therock](https://avatars.discourse-cdn.com/v4/letter/t/ac8455/32.png) [@therock](https://discuss.gradle.org/u/therock)\
**Post date:** [December 9, 2016, 7:38pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/10 "2016-12-09T19:38:22Z")

</div>

So… what’s happening here ( at the same time ill try to take the opportunity of understanding)

We created a task in gradle and

Because right now, I have a VerstionTest in package tests ( src/test/java/tests/VersionTest.java)

However, if I do Version.getVersion() I get a “cannot resolve symbol” on version. I tried to run it through gradle ( ./gradlew test --tests VersionTest.java ) - or any other extension for that matter.

I really don’t know what else to do / add. I don’t know if the rest of my build.gradle file may be interfering with the task generateTestSources

EDIT: I tried doing tests.Version.getVersion() and it solved my problem but it returns an unspecified… weird.

EDIT 2: it worked, just when debugging the actual function is written like this:

```
    package tests;

public class Version {
	public static String getVersion() {
		return "unspecified";
	}
}

```

so I’m guessing in the build.gradle I’m not relaying the variable correctly or something

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<div class="post-metadata">

**Author:** ![therock](https://avatars.discourse-cdn.com/v4/letter/t/ac8455/32.png) [@therock](https://discuss.gradle.org/u/therock)\
**Post date:** [December 9, 2016, 7:55pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/11 "2016-12-09T19:55:05Z")

</div>

It worked, I created a gradle.properties file and put my version in there and relayed it in my build.gradle.

Doing version ‘4.2’ directly in build.gradle didn’t seem to work. Thank you so much for keeping your patience Lance, time for me to go get some tutorial done on gradle haha

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<div class="post-metadata">

**Author:** ![Lance\_Java](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/lance_java/32/787_2.png) [@Lance\_Java](https://discuss.gradle.org/u/Lance_Java)\
**Post date:** [December 9, 2016, 7:59pm UTC](https://discuss.gradle.org/t/accessing-build-graddle-information-from-a-java-file/20756/12 "2016-12-09T19:59:02Z")

</div>

I feel I’ve given enough food for thought including two working examples. Please grok it