Hello World in spring 5 with application context

I started to learn Spring Framework as my first ever app.I tried to get defined Beans count but i can't run it.

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;


public class runDemo {
    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext();
        System.out.println(context.getBeanDefinitionCount());
    }
}

and my gradle file

buildscript {
ext {
    springBootVersion = '1.5.6.RELEASE'
}
repositories {
    mavenCentral()
}
dependencies {
    classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'

version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
mavenCentral()
}


dependencies {

compile('org.springframework.boot:spring-boot-starter')
testCompile('org.springframework.boot:spring-boot-starter-test')
}

and when i run this:

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/context/ApplicationContext
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:123)
Caused by: java.lang.ClassNotFoundException: org.springframework.context.ApplicationContext ...

I have spring context and spring core in the External Libraries loaded.

EDIT:I upgraded to Intellij idea 2017.2 and it still give the same error