*
 * <p>This is a classic &quot;bounded buffer&quot;, in which a fixed-sized array holds elements
 * inserted by producers and extracted by consumers. Once created, the capacity cannot be increased.
 * Attempts to {@code put} an element into a full queue will result in the operation blocking;
 * attempts to {@code take} an element from an empty queue will similarly block.
 *

 *
 * <p>This is a classic &quot;bounded buffer&quot;, in which a fixed-sized array holds elements
 * inserted by producers and extracted by consumers. Once created, the capacity cannot be increased.
 * Attempts to {@code put} an element into a full queue will result in the operation blocking;
 * attempts to {@code take} an element from an empty queue will similarly block.
 *

  Histograms are exposed in both classic and native formats using exponential bucket configuration (factor=1.1, max buckets=160) ([#137779](https://github.com/kubernetes/kubernetes/pull/137779), [@richabanker](https://github.com/richabanker)) [SIG API Machinery, Instrumentation and Testing]
- Enables Prometheus native histogram support in kube-proxy when feature gate is enabled.

  public static void rotate(int[] array, int distance, int fromIndex, int toIndex) {
    // There are several well-known algorithms for rotating part of an array (or, equivalently,
    // exchanging two blocks of memory). This classic text by Gries and Mills mentions several:
    // https://ecommons.cornell.edu/bitstream/handle/1813/6292/81-452.pdf.
    // (1) "Reversal", the one we have here.

import java.util.stream.StreamSupport;

import org.apache.hc.client5.http.config.ConnectionConfig;
import org.apache.hc.client5.http.config.RequestConfig;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuilder;
import org.apache.hc.core5.util.Timeout;
import org.apache.logging.log4j.LogManager;

            Interface12.class,
            Interface1.class,
            Interface2.class,
            Class1.class,
            Object.class);
    makeUnmodifiable(types.interfaces().rawTypes())
        .containsExactly(
            Interface3.class,
            Interface12.class,
            Interface1.class,
            Interface2.class,
            Iterable.class);
    makeUnmodifiable(types.classes().rawTypes())

  @VisibleForTesting
  List<Class<?>> findClassesToTest(
      Iterable<? extends Class<?>> classes, Iterable<String> explicitTestNames) {
    // "a.b.Foo" -> a.b.Foo.class
    TreeMap<String, Class<?>> classMap = Maps.newTreeMap();
    for (Class<?> cls : classes) {
      classMap.put(cls.getName(), cls);
    }
    // Foo.class -> [FooTest.class, FooTests.class, FooTestSuite.class, ...]

- 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)

  @VisibleForTesting
  List<Class<?>> findClassesToTest(
      Iterable<? extends Class<?>> classes, Iterable<String> explicitTestNames) {
    // "a.b.Foo" -> a.b.Foo.class
    TreeMap<String, Class<?>> classMap = Maps.newTreeMap();
    for (Class<?> cls : classes) {
      classMap.put(cls.getName(), cls);
    }
    // Foo.class -> [FooTest.class, FooTests.class, FooTestSuite.class, ...]

mvn license:format                    # Apply license headers
mvn verify                            # Generate coverage report
```

## Code Conventions

### Class Structure

- **Utility classes**: `abstract` class + `protected` constructor
- **Constants classes**: Same pattern

### Argument Validation

Use `AssertionUtil` at method entry:
- `AssertionUtil.assertArgumentNotNull("argName", value)`