我的第一个Springboot应用程序没有启动，因为它给出NoClassDefFoundError

Question

我刚刚使用Java 8设置STS并尝试运行我的第一个springboot helloworld应用程序。虽然我能够通过Pom.xml构建它 - ＆gt;右键单击 - ＆gt; MVN安装......成功构建。但在运行应用程序时，即

DemoApplication.jav a =＆gt;右键单击=＆gt; run as =＆gt; java应用程序。这是我得到的： -

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
        at com.sample.DemoApplication.main(DemoApplication.java:10)
    Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 1 more

这是我的POM.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>com.sample</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>2.19.1</version>
            <configuration>
                <testFailureIgnore>true</testFailureIgnore>
            </configuration>
        </plugin>
        </plugins>
    </build>
</project>
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我在路径环境变量中设置了JAVA_HOME变量和Maven路径（直到bin）。