Spring boot REST application not working without Build Path in Eclipse - eclipse

Question

I'm facing an issue where our spring boot application will only run if a subproject is included. A rough project sketch:
Backend
This is where the Main Class is located. This project also contains the spring repository which are exposed via REST, the filters and REST configuration. The data itself is included in the backend-module project.
backend-module
This is where the actual Java Classes which hold the data are located. They are used in conjunction with hibernate.
Now the application works fine unless I remove the backend-module from the Java Build Path in the eclipse Project preferences. But if I remove the reference the application launch will fail but not for a missing component from the backendmodule but for missing spring boot components:
Caused by: java.lang.NoClassDefFoundError: org/springframework/data/repository/support/RepositoryInvokerFactory
The pom.xml files of the project are almost the same.
I'll happily include all the information someone may need.
Thanks
EDIT 1:
The pom.xml of the Backend Project.
<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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>backend</groupId>
<artifactId>Backend</artifactId>
<version>1.0</version>
<description>Rest Backend</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.2.5.RELEASE</version>
</parent>
<properties>
<!-- use UTF-8 for everything -->
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-io</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>cis</groupId>
<artifactId>backend-module</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.2.12.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-spatial</artifactId>
<version>4.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-rest-webmvc</artifactId>
<version>2.3.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-legacy</artifactId>
<version>1.0.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-commons-core</artifactId>
<version>1.4.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.2.12.Final</version>
</dependency>
<dependency>
<groupId>postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>9.1-901-1.jdbc4</version>
</dependency>
<dependency>
<groupId>org.postgis</groupId>
<artifactId>postgis-jdbc</artifactId>
<version>1.5.2</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>org.antlr</groupId>
<artifactId>ST4</artifactId>
<version>4.0.8</version>
</dependency>
<dependency>
<groupId>jdom</groupId>
<artifactId>jdom</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.5.3</version>
</dependency>
<dependency>
<groupId>org.codehaus.woodstox</groupId>
<artifactId>woodstox-core-asl</artifactId>
<version>4.4.1</version>
</dependency>
<dependency>
<groupId>cis.adapter</groupId>
<artifactId>CISConnector</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>cis.adapter</groupId>
<artifactId>CISCore</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>com.google</groupId>
<artifactId>caplibrary</artifactId>
<version>r11</version>
</dependency>
</dependencies>
<repositories>
<repository>
<id>org.jboss.repository.releases</id>
<name>JBoss Maven Release Repository</name>
<url>https://repository.jboss.org/nexus/content/repositories/releases</url>
</repository>
<repository>
<id>OSGEO GeoTools repo</id>
<url>http://download.osgeo.org/webdav/geotools</url>
</repository>
<repository>
<id>Hibernate Spatial repo</id>
<url>http://www.hibernatespatial.org/repository</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/libs-release</url>
</pluginRepository>
</pluginRepositories>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.2.6.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

Answer 1

Apparently the issue was fixed by dropping a lot of the version statements in the pom.xml files and upgrading Spring Boot to the latest version.
If I understood the hastily given explanation correctly our Spring boot release didn't have the right versions of some Spring components packed into it.
Sorry if someone has a similar issue and finds this answer insufficient.