- Use `OptionalEntity<T>` for nullable returns
- Plain classes (no extends/implements)

### Helper
- Stateless utility classes
- Access via `ComponentUtil.getXyzHelper()`
- Named with "Helper" suffix

### DBFlute Generated Code
```
opensearch/{index}/
├── bsentity/, bsbhv/    # Base classes (DO NOT EDIT)
├── exentity/, exbhv/    # Extended classes (customize here)

     *       <td>{@code /home/user/myproject/target/classes}</td>
     *       <td>No explicit path → use output directory</td>
     *     </tr>
     *     <tr>
     *       <td>{@code Optional.of(Path.of("META-INF"))}</td>
     *       <td>{@code /home/user/myproject/target/classes}</td>
     *       <td>{@code /home/user/myproject/target/classes/META-INF}</td>

        for (String each : violatingClasses) {
            violationsExcludes.add(each);
        }
    }

    public void ignoreJarHellWithJDK(String... classes) {
        for (String each : classes) {
            jdkJarHellExcludes.add(each);
        }
    }

    @Input
    public Set<String> getJdkJarHellExcludes() {
        return jdkJarHellExcludes;
    }

 * }
 * </pre>
 *
 * <p>please use {@link ClassSanityTester#forAllPublicStaticMethods}.
 *
 * <p>If not all classes on the classpath should be covered, {@link #ignoreClasses} can be used to
 * exclude certain classes. As a special case, classes with an underscore in the name (like {@code
 * AutoValue_Foo}) can be excluded using <code>ignoreClasses({@link #UNDERSCORE_IN_NAME})</code>.
 *

  }

  public void testFindClassesToTest_withCorrespondingTestClassAndExplicitlyTested() {
    ImmutableList<Class<?>> classes = ImmutableList.of(Foo.class, FooTest.class);
    assertThat(findClassesToTest(classes, "testPublic")).isEmpty();
    assertThat(findClassesToTest(classes, "testNotThere", "testPublic")).isEmpty();
  }

  public void testFindClassesToTest_withCorrespondingTestClass_noTestName() {

     */
    private static boolean isApplicable(Method method, Class<?>... classes) {
        Class<?>[] methodArgs = method.getParameterTypes();

        if (methodArgs.length != classes.length) {
            return false;
        }

        for (int i = 0; i < classes.length; ++i) {
            if (!isMethodInvocationConvertible(methodArgs[i], classes[i])) {
                return false;
            }
        }

     * preventing deserialization of arbitrary classes that could lead to RCE vulnerabilities.
     * Only explicitly registered classes can be serialized/deserialized.
     * </p>
     */
    public DataSerializer() {
        kryoThreadLocal = ThreadLocal.withInitial(() -> {
            final Kryo kryo = new Kryo();
            // Enable registration requirement for security - only registered classes can be deserialized

        ).buildAndFail();

        assertTaskFailed(result, ":absurd");
        assertOutputContains(result.getOutput(), "Classes with violations:", "  * TestingIO", "> Audit of third party dependencies failed");
        assertOutputMissing(result.getOutput(), "Missing classes:");
        assertNoDeprecationWarning(result);
    }

    public void testClassNotFoundAndCompileOnlyIgnored() {

     */
    boolean isExistClass(final String className);

    /**
     * Searches for classes handled by this instance and calls the handler for each class.
     * <p>
     * If a root package is specified at instance construction, only classes under the root package are targeted.
     * </p>
     *
     * @param handler the handler to process classes
     */
    void forEach(ClassHandler handler);

    /**

    void testTargetPath() {
        Build build = mock(Build.class);
        when(build.getDirectory()).thenReturn("target");
        when(build.getOutputDirectory()).thenReturn("target/classes");
        when(build.getTestOutputDirectory()).thenReturn("target/test-classes");

        Project project = mock(Project.class);
        when(project.getBuild()).thenReturn(build);
        when(project.getBasedir()).thenReturn(Path.of("myproject"));