Exception in thread "main" java.lang.IllegalArgumentException: Source must not be null

    at org.springframework.util.Assert.notNull(Assert.java:115)

    at Test.getaVoid(Test.java:11)

    at Test.main(Test.java:6)

    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

    at java.lang.reflect.Method.invoke(Method.java:497)

    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

import org.springframework.util.Assert;

public class Test {

    public static void main(String[] args) {

        getaVoid();

        System.out.println("hello");

    }

    private static void getaVoid() {

        Assert.notNull(null, "Source must not be null");

    }

}