## Reading a `.env` file { #reading-a-env-file }

If you have many settings that possibly change a lot, maybe in different environments, it might be useful to put them on a file and then read them from it as if they were environment variables.

This practice is common enough that it has a name, these environment variables are commonly placed in a file `.env`, and the file is called a "dotenv".

/// tip

    }

    /**
     * Validate the specified settings.
     *
     * @param settings The settings to validate, must not be {@code null}.
     * @return The list of problems that were encountered, must not be {@code null}.
     */
    @Nonnull
    default ProblemCollector<BuilderProblem> validate(@Nonnull Settings settings) {
        return validate(settings, false);
    }

    /**

 *    default to their previous value.
 *
 * Every [edit] call must be matched by a call to [Editor.commit] or [Editor.abort]. Committing is
 * atomic: a read observes the full set of values as they were before or after the commit, but never
 * a mix of values.
 *
 * Clients call [get] to read a snapshot of an entry. The read will observe the value at the time

    /*
     * Since we use AtomicReferenceFieldUpdaterAtomicHelper by default, we'll "obviously" use it
     * even when Unsafe isn't available. But it's nice to have a check here to make sure that
     * nothing somehow goes wrong as the JDK restricts access to Unsafe.
     */
    checkHelperVersion(NO_UNSAFE, "AtomicReferenceFieldUpdaterAtomicHelper");
    /*

     * method returns {@code true}, it means that element count of stream returned by method {@link #problems()}
     * and the counter returned by {@link #totalProblemsReported()} are not equal (latter is bigger than former).
     *
     * @return true if the problem collector has overflowed and some problems were not preserved
     */
    boolean problemsOverflow();

If not provided, it's `None` by default, here we provide `"World"` as the default value to use.

///

Then you could call that Python program:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// Here we don't set the env var yet
$ python main.py

// As we didn't set the env var, we get the default value

      // should never reach here!
      throw new UnsupportedOperationException();
    }

    @Override
    public Entry<K, V> belowSamplesGreater() {
      // should never reach here!
      throw new UnsupportedOperationException();
    }

    @Override
    public Entry<K, V> aboveSamplesLesser() {
      // should never reach here!
      throw new UnsupportedOperationException();
    }

 * the order they were first added to the multimap. Similarly, {@link #get}, {@link #removeAll}, and
 * {@link #replaceValues} return collections that iterate through the values in the order they were
 * added. The collections generated by {@link #entries()}, {@link #keys()}, and {@link #values}
 * iterate across the key-value mappings in the order they were added to the multimap.
 *

    static String getMessageByCode(final int errcode) {
        /* Note there's a signedness error here because 0xC0000000 based values are
         * negative so it with NT_STATUS_SUCCESS (0) the binary search will not be
         * performed properly. The effect is that the code at index 1 is never found
         * (NT_STATUS_UNSUCCESSFUL). So here we factor out NT_STATUS_SUCCESS
         * as a special case (which it is).
         */

 *
 * Web sockets may fail due to HTTP upgrade problems, connectivity problems, or if either peer
 * chooses to short-circuit the graceful shutdown process:
 *
 *  * **Canceled:** the web socket connection failed. Messages that were successfully enqueued by
 *    either peer may not have been transmitted to the other.
 *
 * Note that the state progression is independent for each peer. Arriving at a gracefully-closed