AWS开发工具包NoClassDefFoundError

Question

I am currently trying to use the AWS SDK (specifically the s3 SDK) in my project but keep getting the exception

java.lang.NoClassDefFoundError:com/amazonaws/services/s3/AmazonS3ClientBuilder

I have imported the SDK into my project using maven as shown in the SDK documentation here . The code that I am running that causes this to occur is

AmazonS3 amazonS3 = AmazonS3ClientBuilder.standard().withRegion(Regions.EU_WEST_1).build();

I suspected the issue may have been occurring due to a conflict in Jackson versions between the version required by the AWS SDK and the version I was importing myself for use else where in the project although changing this does not seem to have resolved the issue. I will include my POM.xml file below.

Thanks in advance.

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.projectname.restservice</groupId>
<artifactId>ProjectName</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>ProjectName</name>

<build>
    <finalName>ProjectName</finalName>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5.1</version>
            <inherited>true</inherited>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey</groupId>
            <artifactId>jersey-bom</artifactId>
            <version>2.16</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-java-sdk-bom</artifactId>
            <version>1.11.22</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet-core</artifactId>
    </dependency>

    <!--Removed due to possible conflict with AWS SDK?-->
    <!--<dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
    </dependency>-->

    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-multipart</artifactId>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.35</version>
    </dependency>

    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-s3</artifactId>
    </dependency>

</dependencies>

Output of: mvn dependency:tree -Dverbose -Dincludes=com.amazonaws

com.trailfinder.restservice:TrailFinderRestService:war:1.0-SNAPSHOT
[INFO] \- com.amazonaws:aws-java-sdk-s3:jar:1.11.22:compile
[INFO]    +- com.amazonaws:aws-java-sdk-kms:jar:1.11.22:compile
[INFO]    |  \- (com.amazonaws:aws-java-sdk-core:jar:1.11.22:compile - omitted for duplicate)
[INFO]    \- com.amazonaws:aws-java-sdk-core:jar:1.11.22:compile

Answer 1

I think, I've found a solution / workaround to this issue. Thanks to suggestions from @DaveMaple I tried building the app through the command line and deploying the .war manually which seems to have worked.

According to this question IntelliJ IDEA uses its own build process and not Mavens. This leads me to believe that the issue was with IntelliJ's build process and nothing to do with AWS SDK or Maven. To work around this issue I configured IntelliJ to not use its own build process but instead to use Maven and then to deploy the resulting .war. Explanation on how to do this can be found here.