We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

All the data conversion, validation, documentation, etc. will still work as normally.

There are three kinds of compatibility we’re tracking:

 * **Binary compatibility** is the ability to compile a program against OkHttp 3.x, and then to run
   it against OkHttp 4.x. We’re using the excellent [japicmp][japicmp] library via its
   [Gradle plugin][japicmp_gradle] to enforce binary compatibility.

 * **Java source compatibility** is the ability to upgrade Java uses of OkHttp 3.x to 4.x without
   changing `.java` files.

import java.util.Collection;
import java.util.Iterator;
import java.util.Objects;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * A multiset which forwards all its method calls to another multiset. Subclasses should override
 * one or more methods to modify the behavior of the backing multiset as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

     * <p>The thread's interrupt bit is cleared before execution of each task.
     *
     * <p>If the Thread in use is interrupted before or during execution of the tasks in {@link
     * #queue}, the Executor will complete its tasks, and then restore the interruption. This means
     * that once the Thread returns to the Executor that this Executor composes, the interruption

            }
        } finally {
            lock.writeLock().unlock();
        }
    }

    /**
     * Shuts down the persistent handle manager and its background tasks
     */
    public void shutdown() {
        shutdown = true;
        scheduler.shutdown();
    }

     */
    boolean problemsOverflow();

    /**
     * Reports a problem: always maintains the counters, but whether problem is preserved in memory, depends on
     * implementation and its configuration.
     *
     * @param problem the problem to report
     * @return {@code true} if passed problem is preserved by this call.
     */
    boolean reportProblem(P problem);

    /**

     * <li>The parent uses aggregation and refers to the child via the modules section</li>
     * <li>The module path to the child is considered to
     * point at the POM rather than its base directory if the path ends with ".xml" (ignoring case)</li>
     * <li>The name of the child's base directory matches the artifact id of the child.</li>
     * </ul>
     * Note that for the sake of independence from the user

You can also create an environment variable only for a **specific program invocation**, that is only available to that program, and only for its duration.

To do that, create it right before the program itself, on the same line:

<div class="termy">

```console
// Create an env var MY_NAME in line for this program call

                }
            }
            clazz = clazz.getSuperclass();
        }
    }

    private String getSingular(String plural) {
        if (plural.endsWith("ies")) {
            return plural.substring(0, plural.length() - 3) + "y";
        }
        if (plural.endsWith("s")) {
            return plural.substring(0, plural.length() - 1);
        }
        return plural;

 * correctly (that is, whether its <i>preconditions</i> were met).
 *
 * <p>If the precondition is not met, the {@code Preconditions} method throws an unchecked exception
 * of a specified type, which helps the method in which the exception was thrown communicate that
 * its caller has made a mistake. This allows constructs such as
 *
 * {@snippet :