@Cacheable not working, still calling the caching method

I am trying to use @Cacheable to cache the roles regardless of the parameter. But the @Cacheable does not quite work and the method would get called twice.

CachingConfig:

@Configuration
@EnableCaching
public class CachingConfig {

    @Bean
    public CacheManager cacheManager(@Value("${caching.ttl.period}") long period,
                                     @Value("${caching.ttl.unit}") String unit) {
        return new ConcurrentMapCacheManager() {
            @Override
            public Cache createConcurrentMapCache(String name) {
                return new ConcurrentMapCache(name, CacheBuilder.newBuilder()
                        .expireAfterWrite(period, TimeUnit.valueOf(unit)).build().asMap(), true);
            }
        };
    }
}

RoleMappingService:

@Service
public class RoleMappingService {
private final AdminClient adminClient;

    public RoleMappingService(AdminClient adminClient) {
        this.adminClient = adminClient;
    }

    @Cacheable(value = "allRoles", key = "#root.method")
    public List<Role> getAllRoles(String sessionToken) {
        AdminSession adminSession = new AdminSession();
        AdminSession.setSessionToken(sessionToken);

        List<RoleGroup> allRoleGroups = this.adminClient.getAllRoleGroups(adminSession)
                .orElse(Collections.emptyList());

        List<Role> allRoles = allRoleGroups
                .stream()
                .map(RoleGroup::getRoles)
                .flatMap(List::stream)
                .collect(Collectors.toList());

        return allRoles;
    }

Test:

@SpringBootTest(classes = Application.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)

public class RoleCachingTest {

    private final JFixture fixture = new JFixture();

    private AdminClient adminClient = mock(AdminClient.class);

    @Test
    public void allRolesShouldBeCached(){
        RoleGroup mockRoleGroup = mock(RoleGroup.class);
        Role mockRole = this.fixture.create(Role.class);

        when(this.adminClient.getAllRoleGroups(any(AdminSession.class)))
                .thenReturn(Optional.of(Arrays.asList(mockRoleGroup)));

        when(mockRoleGroup.getRoles()).thenReturn(Arrays.asList(mockRole));

        RoleMappingService sut = new RoleMappingService(adminClient);

        List<Role> firstRes = sut.getAllRoles(
                fixture.create(String.class));

        List<Role> secondRes = sut.getAllRoles(
                fixture.create(String.class));
        assertEquals(firstRes.size(), secondRes.size());
        assertEquals(firstRes.get(0).getId(), secondRes.get(0).getId());
        assertEquals(firstRes.get(0).getRoleName(), secondRes.get(0).getRoleName());

        // The getAllRoleGroups() should not be called on the second call
        verify(this.adminClient, times(1)).getAllRoleGroups(any(AdminSession.class));

    }

The adminClient.getAllRoleGroups() would always get called twice in this test, while I expect it would only get called once because of @Cacheable.

The project structure:
project structure

I think your @Cacheable annotation is not working because you have not specified Interface for class. This is because of proxy created for caching by Spring. Spring has specified below in its documentation . I thing you have not specified proxy-target-class, it means it will be default to false. If it is false it will use JDK interface based proxies. But in your case you class i.e. RollMappingService is not implementing interface. Create interface RollMappingService with method getAllRoles and implement it, will sole your problem.

> Controls what type of caching proxies are created for classes annotated with the @Cacheable or @CacheEvict annotations. If the proxy-target-class attribute is set to true, then class-based proxies are created. If proxy-target-class is false or if the attribute is omitted, then standard JDK interface-based proxies are created. (See Section 9.6, “Proxying mechanisms” for a detailed examination of the different proxy types.)

Also modify your test class to create Spring bean for RoleMappingService in following ways and inject mock of AdminClient into it

 @Mock
private AdminClient mockedAdminClient;

@InjectMocks
@Autowired
private RoleMappingService roleMappingService

@Before
public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
    ReflectionTestUtils.setField(roleMappingService, 
    "adminClient",
            mockedAdminClient);
}