Gradle : v4.10.3
IDE : IntelliJ
I was facing this issue when using gradle to run my build and test. Copying the applicationContext.xml all over the place did not help. Even specifying the complete path as below did not help !
context = new ClassPathXmlApplicationContext("C:\\...\\applicationContext.xml");
The solution (for gradle at least) lies in the way gradle processes resources. For my gradle project I had laid out the workspace as defined at https://docs.gradle.org/current/userguide/java_plugin.html#sec:java_project_layout
When running a test using default gradle set of tasks includes a "processTestResources" step, which looks for test resources at C:\.....\src\test\resources (Gradle helpfully provides the complete path).
Your .properties file and applicationContext.xml need to be in this directory. If the resources directory is not present (as it was in my case), you need to create it copy the file(s) there. After this, simply specifying the file name worked just fine.
context = new ClassPathXmlApplicationContext("applicationContext.xml");