JUnit5 test error: java.lang.Exception: No tests found matching

My JUnit5 test class is very simple.

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.platform.runner.JUnitPlatform;
import org.junit.runner.RunWith;

@RunWith(JUnitPlatform.class)
public class UmsServiceTest {

    @BeforeEach
    public void setUp() {
    }

    @Test
    public void getPrefixUsernames() {
        assertThat(UmsService.getPrefixedUsername("msun", STAFF), is("user:msun"));
        assertThat(UmsService.getPrefixedUsername("msun", PUBLIC_USER), is("user:public:msun"));
    }

}

Upon running it (by right clicking on the test and 'Run as' -> JUnit test, I get this error.

java.lang.Exception: No tests found matching [{ExactMatcher:fDisplayName=getPrefixUsernames], {ExactMatcher:fDisplayName=getPrefixUsernames(au.gov.nla.ums.keycloak.service.UmsServiceTest)], {LeadingIdentifierMatcher:fClassName=au.gov.nla.ums.keycloak.service.UmsServiceTest,fLeadingIdentifier=getPrefixUsernames]] from org.junit.internal.requests.ClassRequest@77ec78b9
 at org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:40)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createFilteredTest(JUnit4TestLoader.java:80)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:71)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:46)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:522)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)

This is because I have created this class as JUnit 4 class in Eclipse.

And now I am trying to run it as JUnit 5 test case.

To fix this, I need to change the test runner to JUnit 5 by right clicking on the test -> 'Run as' -> Run Configurations, and selecting 'JUnit 5' as the tester runner