* 6.7). Unlike {@link Class#getPackage}, this method only parses the class name, without
   * attempting to define the {@link Package} and hence load files.
   */
  public static String getPackageName(Class<?> clazz) {
    return getPackageName(clazz.getName());
  }

  /**
   * Returns the package name of {@code classFullName} according to the Java Language Specification

        final String path = ClassUtil.getPackageName(this.getClass()).replaceAll("\\.", "/") + "/aaa.html";
        final String contentType = MimeTypeUtil.guessContentType(path);
        assertEquals("text/html", contentType);
    }

    /**
     * @throws Exception
     */
    @Test
    public void testGetFromStream_gif() throws Exception {

    assertThat(Reflection.getPackageName(Iterable.class)).isEqualTo("java.lang");
    assertThat(Reflection.getPackageName("java.MyType")).isEqualTo("java");
    assertThat(Reflection.getPackageName(Iterable.class.getName())).isEqualTo("java.lang");
    assertThat(Reflection.getPackageName("NoPackage")).isEqualTo("");
    assertThat(Reflection.getPackageName(Map.Entry.class)).isEqualTo("java.util");
  }

    assertThat(Reflection.getPackageName(Iterable.class)).isEqualTo("java.lang");
    assertThat(Reflection.getPackageName("java.MyType")).isEqualTo("java");
    assertThat(Reflection.getPackageName(Iterable.class.getName())).isEqualTo("java.lang");
    assertThat(Reflection.getPackageName("NoPackage")).isEqualTo("");
    assertThat(Reflection.getPackageName(Map.Entry.class)).isEqualTo("java.util");
  }

          .toSet();

  public void testClassesHaveOverrides() throws Exception {
    for (ClassInfo info : ClassPath.from(getClass().getClassLoader()).getAllClasses()) {
      if (!GUAVA_PACKAGES.contains(info.getPackageName())) {
        continue;
      }
      if (
      /*
       * At least one of the classes nested inside TypeResolverTest triggers a bug under older JDKs:

        // Assert
        assertTrue(clazz.isInterface(), "Should be an interface");
        assertTrue(Modifier.isPublic(clazz.getModifiers()), "Interface should be public");
        assertEquals("jcifs.smb", clazz.getPackageName(), "Package must match source");
        assertEquals("SessionSetupHandler", clazz.getSimpleName(), "Simple name must match source");
    }

    @Test
    @DisplayName("Interface declares no methods or fields")

        assertThat(ClassUtil.isAssignableFrom(int.class, Integer.class), is(true));
    }

    /**
     *
     */
    @Test
    public void testGetPackageName() {
        assertThat(ClassUtil.getPackageName(getClass()), is("org.codelibs.core.lang"));
    }

    /**
     *
     */
    @Test
    public void testGetShortClassName() {