This idea of **asynchronous** code described above is also sometimes called **"concurrency"**. It is different from **"parallelism"**.

**Concurrency** and **parallelism** both relate to "different things happening more or less at the same time".

But the details between *concurrency* and *parallelism* are quite different.

To see the difference, imagine the following story about burgers:

### Concurrent Burgers

    /**
     * ProjectBuilder parallelism.
     *
     * @since 4.0.0
     */
    @Config(type = "java.lang.Integer", defaultValue = "cores/2 + 1")
    public static final String MAVEN_MODEL_BUILDER_PARALLELISM = "maven.modelBuilder.parallelism";

    /**
     * User property for enabling/disabling the consumer POM feature.
     *

					updates <- cache.clone()
					return
				}
				cache.replace(v.Name, v.Parent, v.Entry)
				cache.Info.LastUpdate = time.Now()
			}
		}
	}()

	// Restrict parallelism for disk usage scanner
	// upto GOMAXPROCS if GOMAXPROCS is < len(disks)
	maxProcs := runtime.GOMAXPROCS(0)
	if maxProcs < len(disks) {
		disks = disks[:maxProcs]
	}

	// Start one scanner per disk

        performProjectActivation(context, request.getProjectActivation());
        performProfileActivation(context, request.getProfileActivation());

        //
        // Builder, concurrency and parallelism
        //
        // We preserve the existing methods for builder selection which is to look for various inputs in the threading

     */
    public Enumeration<?> propertyNames() {
        return Collections.enumeration(storage.keySet());
    }

    /**
     * Calls the map method put. Provided for parallelism with the getProperty method.
     * Enforces use of strings for property keys and values. The value returned is the result of the map call to put.
     *
     * @param key the key to be placed into this property list.

    BlockingQueue<Future<T>> futureQueue = Queues.newLinkedBlockingQueue();
    long timeoutNanos = unit.toNanos(timeout);

    // For efficiency, especially in executors with limited
    // parallelism, check to see if previously submitted tasks are
    // done before submitting more of them. This interleaving
    // plus the exception mechanics account for messiness of main
    // loop.

    try {

        if (localRepositoryPath != null) {
            request.setLocalRepositoryPath(localRepositoryPath);
        }

        //
        // Builder, concurrency and parallelism
        //
        // We preserve the existing methods for builder selection which is to look for various inputs in the threading

      converts them into `NoOp`s instead.

*   `tf.data`

    * `tf.data` now has an `autotune_options.initial_parallelism` option to
      control the initial parallelism setting used by autotune before the data
      pipeline has started running. The default is 16. A lower value reduces
      initial memory usage, while a higher value improves startup time.

## Keras

- Fixed panic in Job controller when `podRecreationPolicy: Failed` is used, and the number of terminating pods exceeds parallelism. ([#121147](https://github.com/kubernetes/kubernetes/pull/121147), [@kannon92](https://github.com/kannon92))

        return parallelize(subProjectTestClassTimes, testCoverage) { numberOfBatches ->
            if (testCoverage.os == Os.LINUX)
                ParallelizationMethod.TestDistribution
            else
                ParallelizationMethod.TeamCityParallelTests(numberOfBatches)
        }
    }

    private fun parallelize(
        subProjectTestClassTimes: List<SubprojectTestClassTime>,