[SOLVED] build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing

I am trying to get this project to work, https://bitbucket.org/doklovic_atlassian/atlassian-beer-supply/downloads

I had to get few libraries to get the dependencies. But still I'm getting an error:

Some problems were encountered while processing the POMs: [WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 156, column 21 [ERROR] Unresolveable build extension: Plugin com.atlassian.maven.plugins:maven-jira-plugin:6.0.0 or one of its dependencies could not be resolved: Failed to collect dependencies for com.atlassian.maven.plugins:maven-jira-plugin:jar:6.0.0 () @ [ERROR] Unknown packaging: atlassian-plugin @ line 14, column 16 (at line 3)

This is the pom.xml for the project,

http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>
<groupId>com.example.beersupply</groupId>
<artifactId>atlassian-beer-supply</artifactId>
<version>1.0-SNAPSHOT</version>
<organization>
    <name>Example Company</name>
    <url>http://www.example.com/</url>
</organization>
<name>atlassian-beer-supply</name>

<description>This is the com.example.beersupply:atlassian-beer-supply plugin for Atlassian JIRA.</description>

<packaging>atlassian-plugin</packaging>
<dependencies>
    <dependency>
        <groupId>com.atlassian.jira</groupId>
        <artifactId>jira-api</artifactId>
        <version>${jira.version}</version>
        <scope>provided</scope>
    </dependency>
    <!-- Add dependency on jira-core if you want access to JIRA implementation classes as well as the sanctioned API. -->
    <!-- This is not normally recommended, but may be required eg when migrating a plugin originally developed against JIRA 4.x -->
    <!-- WE ARE ADDING THIS IN SO WE HAVE THE CORE CLASSES NEEDED TO CREATE A WORKFLOW -->
    <dependency>
        <groupId>com.atlassian.jira</groupId>
        <artifactId>jira-core</artifactId>
        <version>${jira.version}</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>com.atlassian.plugins</groupId>
        <artifactId>atlassian-plugins-core</artifactId>
        <version>3.2.5</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.8.1</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.atlassian.jira</groupId>
        <artifactId>jira-tests</artifactId>
        <version>${jira.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.mockito</groupId>
        <artifactId>mockito-all</artifactId>
        <version>1.9.0</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.4</version>
        <scope>provided</scope>
    </dependency>
    <!-- added this for activeobjects support -->
    <dependency>
        <groupId>com.atlassian.activeobjects</groupId>
        <artifactId>activeobjects-plugin</artifactId>
        <version>0.29.3</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>net.java.dev.activeobjects</groupId>
        <artifactId>activeobjects-test</artifactId>
        <version>0.29.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.atlassian.activeobjects</groupId>
        <artifactId>activeobjects-test</artifactId>
        <version>0.29.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.derby</groupId>
        <artifactId>derby</artifactId>
        <version>10.4.2.0</version>
        <scope>test</scope>
    </dependency>
    <!-- added this for template renderer support -->
    <dependency>
        <groupId>com.atlassian.templaterenderer</groupId>
        <artifactId>atlassian-template-renderer-api</artifactId>
        <version>1.5.7</version>
        <scope>provided</scope>
    </dependency>
    <!-- added this to parse json responses -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>1.7.2</version>
    </dependency>
    <!-- rest junk -->
    <dependency>
        <groupId>javax.ws.rs</groupId>
        <artifactId>jsr311-api</artifactId>
        <version>1.1</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.xml.bind</groupId>
        <artifactId>jaxb-api</artifactId>
        <version>2.1</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>com.atlassian.plugins.rest</groupId>
        <artifactId>atlassian-rest-common</artifactId>
        <version>2.9.10</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>com.atlassian.jira</groupId>
        <artifactId>atlassian-jira-pageobjects</artifactId>
        <version>${jira.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.3.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.wink</groupId>
        <artifactId>wink-client-apache-httpclient</artifactId>
        <version>1.1.3-incubating</version>
        <scope>test</scope>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>com.atlassian.maven.plugins</groupId>
            <artifactId>maven-jira-plugin</artifactId>
            <version>${amps.version}</version>
            <extensions>true</extensions>
            <configuration>
                <productVersion>${jira.version}</productVersion>
                <productDataVersion>${jira.version}</productDataVersion>
                <instructions/>
            </configuration>
        </plugin>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>
    </plugins>
</build>
<properties>
    <jira.version>6.3.4</jira.version>
    <jira.data.version>6.3.4</jira.data.version>
    <amps.version>6.0.0</amps.version>
</properties>

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I would highly appreciate if someone could point out, what I might be missing here. Thank you.