Develop Reference

Multiple steps for spotless format java error while gradle build

There is an IntelliJ project using Gradle, Java and in one of the modules, I put the Java code which is working independently. But on moving the code within this project and running the build.gradle I am getting the following error:
Could not create task ':wlcr-auto-api:spotlessJavaApply'. Could not
create task ':wlcr-auto-api:spotlessJava'. Multiple steps with name
'google-java-format' for spotless format 'java'
I am not sure what is the reason for this error. Also, I am not sure if the project structure is correct in Intellij.
In the above image auto is the project that was already created. I created a new module auto-api and put all my code inside it. There is an Application.java inside it, the main file to run the spring boot application. It works when the code is not put inside this auto project. But not when included in the project.
I have no clue how to debug this.

check out your build.gradle - probably you missed something inside block:
spotless {
...
}
at least, if you simply remove it - the issue will gone

What to do as AndroidSlidingUpPanel Library is using some libraries not up to date

I was trying to use AndroidSlidingUpPanel in my app but when I was trying to build the Gradle file is giving me this warning.
All com.android.support libraries must use the exact same version specification (mixing versions can lead to runtime crashes). Found versions 26.0.0-alpha1, 23.4.0. Examples include com.android.support:animated-vector-drawable:26.0.0-alpha1 and com.android.support:recyclerview-v7:23.4.0 more...
I have seen the files in GitHub and saw that the file AndroidSlidingUpPanel/library/build.gradle is using a lower version of :
compile 'com.android.support:support-v4:23.4.0'
compile 'com.android.support:support-annotations:23.4.0'
compile 'com.android.support:recyclerview-v7:23.4.0'
which should be something like this:
compile 'com.android.support:support-v4:26.+'
compile 'com.android.support:support-annotations:26.+'
compile 'com.android.support:recyclerview-v7:26.+'
When I downloaded the library and imported it as module it was giving error too:
Error:(21, 0) Could not read script
'I:\ANDROID\Android_Studio_Projects\TRYS\Theme3\maven_push.gradle' as it
does not exist.
Open File
Even after copying maven_push.gradle to root it is giving this error:Error:Could not get unknown property 'GROUP' for object of type org.gradle.api.publication.maven.internal.deployer.DefaultGroovyMavenDeployer.
So what to do?

open android studio and get to this page
press this part
it will open a drop-down menu press git and then
press clone and your done

You have two options
Post an issue in the library on GitHub and wait for the creator to update.
Add it to your project manually by pulling​ the project from git and update the libraries your self.

Remove lines referring to maven_push.gradle from the build.gradle on the specified project.
Example:
apply from: 'https://raw.github.com/chrisbanes/gradle-mvn-push/master/gradle-mvn-push.gradle'
apply from: './mvn-push.gradle'
Just comment them out. I've got this solution after going through this

How do I make error-prone ignore my generated source code?

I've recently discovered Error Prone and am integrating it into my Android build using the Gradle plugin linked on their page.
Since our project is using Icepick (and some other code generating annotation processors), we have generated source code, which gets compiled in. Unfortunately, some of the generated code triggers warnings in Error Prone, and I'd like to filter that noise out somehow.
The generated code shows up in the app/build/generated/source/apt/debug directory. How can I exempt this code from Error Prone's steely gaze?

Use the flag -XepDisableWarningsInGeneratedCode
See this issue on GitHub

In my case classes were annotated with #AvroGenerated and -XepDisableWarningsInGeneratedCode didn't work.
The solution was to exclude build directory from checks via -XepExcludedPaths:.*/build/.*

Can I force the order of dependencies in my classpath with Gradle?

A project runs on Google App Engine. The project has dependency that uses a class that can't be invoked on App Engine due to security constraints (it's not on the whitelist). My (very hacky) solution was to just copy a modified version of that class into my project (matching the original Class's name and package) that doesn't need the restricted class. This works on both dev and live, I assume because my source appears in the classpath before my external dependencies.
To make it a bit cleaner, I decided to put my modified version of that class into it's own project that can be packaged up in a jar and published for anyone else to use should they face this problem.
Here's my build.gradle:
// my jar that has 'fixed' version of Class.
compile files('path/to/my-hack-0.0.1.jar')
// dependency that includes class that won't run on appengine
compile 'org.elasticsearch:elasticsearch:1.4.4'
On my local dev server, this works fine, the code finds my hacked version of the class first at runtime. On live, for some unknown reason, the version in the elasticsearch dependency is loaded first.
I know having two versions of the same class in the classpath isn't ideal but I was hoping I could reliably force my version to be at the start of the classpath. Any ideas? Alternatively, is there a better way to solve this problem?

Not really sure if this is what people visiting this question were looking for, but this was what my problem and a solution that I reached at.
Jar A: contains class XYZ
Jar B: also contains class XYZ
My Project needs Jar B on the classpath before Jar A to be able to get compiled.
Problem is Gradle sorts the dependencies based on alphabetical order post resolving them which meant Jar B will be coming after Jar A in the generated classpath leading to error while compiling.
Solution:
Declare a custom configuration and patch the compileClasspath. This is how the relevant portion of build.gradle might look like.
configurations {
priority
sourceSets.main.compileClasspath = configurations.priority + sourceSets.main.compileClasspath
}
dependencies {
priority 'org.blah:JarB:2.3'
compile 'org.blah:JarA:2.4'
...
}

It's the app engine classloader I should have been investigating, not gradle...
App Engine allows you to customise the class loader JAR ordering with a little bit of xml in your appengine-web.xml. In my case:
<class-loader-config>
<priority-specifier filename="my-hack-0.0.1.jar"/>
</class-loader-config>
This places my-hack-0.0.1.jar as the first JAR file to be searched for classes, barring those in the directory war/WEB-INF/classes/.
...Thanks to a nudge in the right direction from #Danilo Tommasina :)
UPDATE 2020:
I just hit the same problem again and came across my own question... This time, live appengine was loading a different version of org.json than was being loaded in dev. Very frustrating and no amount of fiddling the build script would fix it. For future searchers, if you're getting this:
java.lang.NoSuchMethodError: org.json.JSONObject.keySet()Ljava/util/Set;
It's because it's loading an old org.json dependency from god-knows-where. I fixed it by adding this to my appengine-web.xml:
<class-loader-config>
<priority-specifier filename="json-20180130.jar"/>
</class-loader-config>
You'll also need a matching dependency in build.gradle if you don't already have one:
compile 'org.json:json:20180130'

According to gradle dependencies documentation, the order of dependencies defines the order in the classpath. So, we can simply put the libraries in the correct order in "dependencies".
But beware! here are two rules with higher priorities:
For a dynamic version, a 'higher' static version is preferred over a 'lower' version.
Modules declared by a module descriptor file (Ivy or POM file) are preferred over modules that have an artifact file only.

Using jackson-dataformat-xml on android

I'm strugling with using jackson-dataformat-xml on android
I have some very basic code that works fine on oracle jre
JacksonXmlModule module = new JacksonXmlModule();
module.setDefaultUseWrapper(false);
XmlMapper xmlMapper = new XmlMapper(module);
First I tried official documentation adapted for gradle (by me, not sure if done correctly):
compile 'com.fasterxml.jackson.core:jackson-core:2.5.4'
compile 'com.fasterxml.jackson.core:jackson-annotations:2.5.4'
compile 'com.fasterxml.jackson.core:jackson-databind:2.5.4'
compile 'com.fasterxml.jackson.dataformat:jackson-dataformat-xml:2.5.4'
compile 'org.codehaus.woodstox:woodstox-core-asl:4.4.1'
compile 'javax.xml.stream:stax-api:1.0-2'
Result: gradle fails build time about bundling corelibraries into an application
...
:app:preDexDebug
trouble processing "javax/xml/stream/EventFilter.class":
Ill-advised or mistaken usage of a core class (java.* or javax.*)
when not building a core library.
...
2nd attempt trying to follow Sean's answer
(Basicly he repackages corelibs with prefix names and rebuilds jackson-dataformat-xml to use the prefixed names)
compile 'com.fasterxml.jackson.core:jackson-core:2.1.2'
compile 'com.fasterxml.jackson.core:jackson-annotations:2.1.2'
compile 'com.fasterxml.jackson.core:jackson-databind:2.1.2'
// Repackaged XML-specific libraries
compile 'edu.usf.cutr.android.xml:jackson-dataformat-xml-android:2.1.2'
compile 'edu.usf.cutr.android.xml:stax2-api-android:3.1.1'
compile 'edu.usf.cutr.android.xml:stax-api-android:1.0-2'
compile 'edu.usf.cutr.android.xml:aalto-xml-android:0.9.8'
And build time failed on duplicates
Duplicate files copied in APK META-INF/services/com.fasterxml.jackson.core.ObjectCodec
so added:
packagingOptions {
...
exclude 'META-INF/services/com.fasterxml.jackson.core.JsonFactory'
exclude 'META-INF/services/com.fasterxml.jackson.core.ObjectCodec'
}
When adding the exclusions it builds and deploys, but fails runtime on below stackdump (AFAIK it cant find the SAX provider, even tho it is added to the classpath to my understanding)
edu.usf.cutr.javax.xml.stream.FactoryConfigurationError: Provider com.bea.xml.stream.MXParserFactory not found
at edu.usf.cutr.javax.xml.stream.FactoryFinder.newInstance(FactoryFinder.java:72)
at edu.usf.cutr.javax.xml.stream.FactoryFinder.find(FactoryFinder.java:176)
at edu.usf.cutr.javax.xml.stream.FactoryFinder.find(FactoryFinder.java:92)
at edu.usf.cutr.javax.xml.stream.XMLInputFactory.newInstance(XMLInputFactory.java:136)
at com.fasterxml.jackson.dataformat.xml.XmlFactory.<init>(XmlFactory.java:97)
at com.fasterxml.jackson.dataformat.xml.XmlFactory.<init>(XmlFactory.java:85)
at com.fasterxml.jackson.dataformat.xml.XmlFactory.<init>(XmlFactory.java:82)
at com.fasterxml.jackson.dataformat.xml.XmlMapper.<init>(XmlMapper.java:46)
What is the proper way to move forward on either #1 or #2?

Number 2 is the correct approach (Android doesn't like it when you include classes in the official Java package namespace - but then again, I wrote the original answer so I'm biased ;) ).
I believe the FactoryConfigurationError: Provider com.bea.xml.stream.MXParserFactory not found error is due to a bug in the Android build tools. In previous versions of ADT for Eclipse and Gradle plugin < 0.7.0 the /META-INF/* files are stripped from the JARs during the build process. It seems like >= v0.7.0 shouldn't have the problem according to Google, but from others' reports it sounds like it still may be problematic, and could potentially remove the META-INF/services/javax.xml.stream.XMLInputFactory file, which is required for the platform to register Aalto.
Try the workaround mentioned in AOSP issue 59658 comment 22:
right click on /src/main (where you have /java and /res folders),
select New > Folder > Java Resources Folder,
click Finish (do not change Folder Location),
right click on new /resources folder,
select New > Directory
enter "META-INF" (without quotes),
right click on /resources/META-INF folder,
select New > Directory
enter "services" (without quotes)
copy any file you need into /resources/META-INF/services
For you, in step 10 above you'd need to copy this file into /resources/META-INF/services. In case the file link is broken in the future, the name of the file is javax.xml.stream.XMLInputFactory and it consists of a single line:
com.fasterxml.aalto.stax.InputFactoryImpl
EDIT
If you get a "Error:duplicate files during packaging of APK... Path in archive: META-INF/services/javax.xml.stream.XMLInputFactory", you can try telling Gradle to keep the first occurrence with:
android {
packagingOptions {
pickFirst 'META-INF/services/javax.xml.stream.XMLInputFactory'
}
}
EDIT 2
This bug may be affecting "pickFirst". Please make sure you're running the latest version of Android Studio, and update your local tools and Android Gradle plugin to make sure you're running the most recent version of the tools. This may be fixed in Android Studio 1.3 RC1.

I have attempted to add XmlPull support to jackson xml. Find the forked project here:
https://github.com/finvu/jackson-dataformat-xml
Currently, only supported for version 2.9.6. (clone the branch jackson-dataformat-xml-2.9.6-XmlPull)
Sorry, I am not able to provide detailed documentation due to time constraints. If you have knowledge of git and maven to pull a specific branch and build the jar, then it should be relatively easy.

To those who will be in need of this in the future:
first integrate Jitpack in Your Android app, following their instructions:
https://jitpack.io/
Then paste teh GitHub url of jackson-dataformat-xml on Jitpack sites' corresponding text box. GitHub url is:
https://github.com/FasterXML/jackson-dataformat-xml.
That's it! Enjoy the result. :)