java.lang.ClassNotFoundException on ClasspathPropertiesFileCredentialsProvider in a Kotlin project for Windows - amazon-web-services

Question

I created a console application for Windows in Kotlin.
In that app, I want to send files to an AWS S3 bucket.
For that purpose, I initiate my S3 client like the following:
// credentials provider :
val classpathPropertiesFileCredentialsProvider = ClasspathPropertiesFileCredentialsProvider("AWSCredentials.properties")
// S3 client :
val amazonS3: AmazonS3 = AmazonS3ClientBuilder.standard()
.withRegion("eu-central-1")
.withCredentials(classpathPropertiesFileCredentialsProvider)
.build()
And here are all the imports in my build.gradle file:
implementation 'com.amazonaws:aws-java-sdk-opensdk:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-core:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-apigatewayv2:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-cognitoidentity:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-cognitoidp:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-s3:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-sts:1.12.58'
implementation 'com.amazonaws:aws-java-sdk-s3control:1.12.58'
The project compiles without any error, but when I run it, I get the following error:
java.lang.ClassNotFoundException: com.amazonaws.auth.ClasspathPropertiesFileCredentialsProvider
which I don't understand, since I did the same in another Java Swing project, and it works fine.
Did I miss something?
Thanks.

Answer 1

To work with Kotlin and AWS Services such as Amazon S3, you should consider using the AWS SDK for Kotlin. This is a newer SDK built for Kotlin developers. You are currently using the AWS SDK for Java V1. If you are using Java, then you should move from V1 to Java V2.
To learn how to get started with the AWS SDK for Kotlin, see this topic:
https://github.com/awslabs/aws-sdk-kotlin/blob/main/docs/GettingStarted.md
To work with Amazon S3 and Kotlin, refer to the code examples in Github here.
To upload a file to an Amazon S3 bucket using the Kotlin SDK, use this code:
package com.kotlin.s3
// snippet-start:[s3.kotlin.s3_object_upload.import]
import aws.sdk.kotlin.services.s3.S3Client
import aws.sdk.kotlin.services.s3.model.PutObjectRequest
import aws.sdk.kotlin.services.s3.model.S3Exception
import aws.smithy.kotlin.runtime.content.ByteStream
import java.io.File
import java.io.FileInputStream
import java.io.IOException
import kotlin.system.exitProcess
// snippet-end:[s3.kotlin.s3_object_upload.import]
/**
To run this Kotlin code example, ensure that you have setup your development environment,
including your credentials.
For information, see this documentation topic:
https://docs.aws.amazon.com/sdk-for-kotlin/latest/developer-guide/setup.html
*/
suspend fun main(args: Array<String>) {
val usage = """
Usage:
<bucketName> <objectKey> <objectPath>
Where:
bucketName - the Amazon S3 bucket to upload an object into.
objectKey - the object to upload (for example, book.pdf).
objectPath - the path where the file is located (for example, C:/AWS/book2.pdf).
"""
if (args.size != 3) {
println(usage)
exitProcess(0)
}
val bucketName = args[0]
val objectKey = args[1]
val objectPath = args[2]
val s3Client = S3Client { region = "us-east-1" }
putS3Object(s3Client, bucketName, objectKey, objectPath)
s3Client.close()
}
// snippet-start:[s3.kotlin.s3_object_upload.main]
suspend fun putS3Object(
s3Client: S3Client,
bucketName: String,
objectKey: String,
objectPath: String
){
try {
val metadataVal = mutableMapOf<String, String>()
metadataVal["myVal"] = "test"
val putOb = PutObjectRequest {
bucket = bucketName
key = objectKey
metadata = metadataVal
this.body = ByteStream.fromBytes(getObjectFile(objectPath))
}
val response =s3Client.putObject(putOb)
println("Tag information is ${response.eTag}")
} catch (e: S3Exception) {
println(e.message)
s3Client.close()
exitProcess(0)
}
}
fun getObjectFile(filePath: String): ByteArray {
var fileInputStream: FileInputStream? = null
lateinit var bytesArray: ByteArray
try {
val file = File(filePath)
bytesArray = ByteArray(file.length().toInt())
fileInputStream = FileInputStream(file)
fileInputStream.read(bytesArray)
} catch (e: IOException) {
println(e.message)
} finally {
if (fileInputStream != null) {
try {
fileInputStream.close()
} catch (e: IOException) {
println(e.message)
}
}
}
return bytesArray
}
NOTE that all examples assume that your creds are located in a file named credentials as explained here:
Setting the default credentials