public void testToOptionalNull() {
    Stream<@Nullable Object> stream = Stream.of((Object) null);
    assertThrows(NullPointerException.class, () -> stream.collect(toOptional()));
  }

  public void testToOptionalMultiple() {
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> Stream.of(1, 2).collect(toOptional()));
    assertThat(expected.getMessage()).contains("1, 2");
  }

/**
 * @author koichik
 */
public class ClassLoaderUtilTest {

    /**
     * @throws Exception
     */
    @Test
    public void testGetClassLoader() throws Exception {
        assertThat(ClassLoaderUtil.getClassLoader(Object.class), is(sameInstance(ClassLoaderUtil.class.getClassLoader())));

        assertThat(ClassLoaderUtil.getClassLoader(TestCase.class), is(sameInstance(TestCase.class.getClassLoader())));

  public void testOfNullKey() {
    assertThrows(NullPointerException.class, () -> ImmutableMap.of(null, 1));

    assertThrows(NullPointerException.class, () -> ImmutableMap.of("one", 1, null, 2));
  }

  public void testOfNullValue() {
    assertThrows(NullPointerException.class, () -> ImmutableMap.of("one", null));

    assertThrows(NullPointerException.class, () -> ImmutableMap.of("one", 1, "two", null));
  }

import com.google.common.collect.ImmutableSet;
import java.util.Collections;
import java.util.Set;
import org.junit.After;
import org.junit.Test;

/**
 * Abstract base class for testing directed {@link Network} implementations defined in this package.
 */
public abstract class AbstractStandardDirectedNetworkTest extends AbstractNetworkTest {

  @After
  public void validateSourceAndTarget() {
    for (Integer node : network.nodes()) {

import org.dbflute.dbway.DBDef;
import org.dbflute.util.DfTypeUtil;

/**
 * @author ESFlute (using FreeGen)
 */
public class RelatedQueryDbm extends AbstractDBMeta {

    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

    // ===================================================================================

import org.dbflute.dbway.DBDef;
import org.dbflute.util.DfTypeUtil;

/**
 * @author ESFlute (using FreeGen)
 */
public class RequestHeaderDbm extends AbstractDBMeta {

    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

    // ===================================================================================

import org.dbflute.dbway.DBDef;
import org.dbflute.util.DfTypeUtil;

/**
 * @author ESFlute (using FreeGen)
 */
public class RoleTypeDbm extends AbstractDBMeta {

    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

    // ===================================================================================

import org.dbflute.dbway.DBDef;
import org.dbflute.util.DfTypeUtil;

/**
 * @author ESFlute (using FreeGen)
 */
public class BoostDocumentRuleDbm extends AbstractDBMeta {

    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

    // ===================================================================================

import org.dbflute.dbway.DBDef;
import org.dbflute.util.DfTypeUtil;

/**
 * @author ESFlute (using FreeGen)
 */
public class DuplicateHostDbm extends AbstractDBMeta {

    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

    // ===================================================================================

    } catch (AssertionFailedError error) {
      // expected
      assertContains("expected:<class ", error.getMessage());
    }
    assertFalse(errorNotThrown);
  }

  private static class ClassWhichDoesNotImplementEquals implements Serializable {
    private static final long serialVersionUID = 1L;
  }

  private static class ClassWhichIsAlwaysEqualButHasDifferentHashcodes implements Serializable {