You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

// A Reader wraps an io.Reader and computes the
// MD5 checksum of the read content as ETag.
//
// Optionally, a Reader can also verify that
// the computed ETag matches an expected value.
// Therefore, it compares both ETags once the
// underlying io.Reader returns io.EOF.
// If the computed ETag does not match the
// expected ETag then Read returns a VerifyError.
//
// Reader implements the Tagger interface.
type Reader struct {
	src io.Reader

package com.google.common.collect;

import java.util.Random;

/**
 * Utility class for being able to seed a {@link Random} value with a passed in seed from a
 * benchmark parameter.
 *
 * <p>TODO: Remove this class once Caliper has a better way.
 *
 * @author Nicholaus Shupe
 */
public final class SpecialRandom extends Random {
  public static SpecialRandom valueOf(String s) {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package target

import (
	"sync"
	"sync/atomic"
)

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

type lazyInit struct {
	done uint32
	m    sync.Mutex
}

func (l *lazyInit) Do(f func() error) error {

      // If the worker is not yet running, the delegate Executor might reject our attempt to start
      // it. To preserve FIFO order and failure atomicity of rejected execution when the same
      // Runnable is executed more than once, allocate a wrapper that we know is safe to remove by
      // object identity.
      // A data structure that returned a removal handle from add() would allow eliminating this
      // allocation.
      submittedTask =

      // If the worker is not yet running, the delegate Executor might reject our attempt to start
      // it. To preserve FIFO order and failure atomicity of rejected execution when the same
      // Runnable is executed more than once, allocate a wrapper that we know is safe to remove by
      // object identity.
      // A data structure that returned a removal handle from add() would allow eliminating this
      // allocation.
      submittedTask =

mc admin trace --all --verbose myminio
```

## Subnet Health

 * therefore every method of the listener will be called at most once. N.B. The {@link State#FAILED}
 * and {@link State#TERMINATED} states are terminal states, once a service enters either of these
 * states it cannot ever leave them.
 *
 * <p>Implementors of this interface are strongly encouraged to extend one of the abstract classes

var (
	errLifecycleTooManyRules = Errorf("Lifecycle configuration allows a maximum of 1000 rules")
	errLifecycleNoRule       = Errorf("Lifecycle configuration should have at least one rule")
	errLifecycleDuplicateID  = Errorf("Rule ID must be unique. Found same ID for more than one rule")
	errXMLNotWellFormed      = Errorf("The XML you provided was not well-formed or did not validate against our published schema")

But here's the key point.

The security and dependency injection stuff is written once.

And you can make it as complex as you want. And still, have it written only once, in a single place. With all the flexibility.

But you can have thousands of endpoints (*path operations*) using the same security system.