Why Mockito can't mock a generic parameter type with number type in Kotlin?

We're moving our project to the Kotlin language. We decided to start from tests but faced with some strange behavior.

Here is our test case:

Service.java

public final class Service {
    private final JdbcTemplate jdbcTemplate;

    public Service(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    public long check() {
        return jdbcTemplate.queryForObject("SELECT COUNT(*) FROM table", Long.class);
    }
}

JavaTest.java (works fine)

@RunWith(MockitoJUnitRunner.class)
public final class JavaTest {
    @Mock
    private JdbcTemplate jdbcTemplate;

    @InjectMocks
    private Service testSubject;

    @Test
    public void test() {
        //given
        when(jdbcTemplate.queryForObject(anyString(), eq(Long.class))).thenReturn(1L);

        //when
        long result = testSubject.check();

        //then
        assertThat(result, is(1L));
    }
}

KotlinTest.kt (not working)

@RunWith(MockitoJUnitRunner::class)
class KotlinTest {
    @Mock
    private lateinit var jdbcTemplate: JdbcTemplate

    @InjectMocks
    private lateinit var testSubject: Service

    @Test
    fun test() {
        //given
        `when`(jdbcTemplate.queryForObject(anyString(), eq(Long::class.java))).thenReturn(1L)

        //when
        val result = testSubject.check()

        //then
        assertThat(result, `is`(1L))
    }
}

Kotlin test fails with NullPointerException:

java.lang.NullPointerException
    at c.i.Service.check(Service.java:13)
    at c.i.KotlinTest.test(KotlinTest.kt:30)

Also, MockitoHint says:

[MockitoHint] KotlinTest.test (see javadoc for MockitoHint):
[MockitoHint] 1. Unused... -> at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:500)
[MockitoHint]  ...args ok? -> at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:500)

Can someone describe what is happening here? I'm quite new to Kotlin and might miss something.

Dependencies version: Kotlin 1.1.3-2, Mockito 2.7.19