下面是代码,
class Z{
static int peekj(){
return j;
}
static int peekk(){
return k;
}
static int i = peekj();
static int h = peekk();
static final int j = 1;
static int k = 1;
}
public class ClassAndInterfaceInitialization {
public static void main(String[] args) {
System.out.println(Z.i);
System.out.println(Z.h);
}
}
遵循静态初始化的前向引用规则后,我将输出视为:
1
0
之后class Z被加载及链接,在初始化阶段,可变 j感final非常首先初始化1.变量k也用1.初始化.
但输出给出0变量k.
我怎么理解这个？
注意:编译器实际上替换j了前向引用规则后引用的变量值,而不像k
在java.util.Map(如下所示),类型参数<K, V>的Entry超过遮蔽类型参数<K, V>的Map.
interface Map<K,V> {
......
interface Entry<K,V> {
.....
}
}
class DblyLinkList从这里有以下内部类DListNode,不需要黯然失色的类型参数T.
public class DblyLinkList<T> implements Iterable<T> {
.......
class DListNode {
private T item;
private DListNode prev;
private DListNode next;
DListNode(T item, DListNode p, DListNode n) {
this.item = item;
this.prev = p;
this.next = n;
}
}
......
}
你能帮我理解一下阴影类型参数的原因Map吗？
下面是docker inspect image redisredis镜像的manifest文件入口snippet( )
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay2/bd512eb256c8aa56cbe9243d440a311820712d1a245fe6f523d39d19cd6c862d/diff:/var/lib/docker/overlay2/7fa1e90f35c78fc83c3a
4b86e36e45d742383b394adf9ce4cf9b339d919c9cbe/diff:/var/lib/docker/overlay2/2c1869386b5b8542959da4f0173a5272b9703326d619f27258b4edff7a1dbbf9/diff:/var/lib/docker/overlay2
/23ba3955c5b72ec17b9c409bd5233a3d92cbd75543c7d144b364f8188765788e/diff:/var/lib/docker/overlay2/87d8a92919103e8ff723221200acb36e17c611fa499571ab183d0f51458e6f24/diff",
"MergedDir": "/var/lib/docker/overlay2/e503ed41978e99fe9b71a4225763a40b7988e9a4f31d4c06ef1ec1af46b0b6ab/merged",
"UpperDir": "/var/lib/docker/overlay2/e503ed41978e99fe9b71a4225763a40b7988e9a4f31d4c06ef1ec1af46b0b6ab/diff",
"WorkDir": "/var/lib/docker/overlay2/e503ed41978e99fe9b71a4225763a40b7988e9a4f31d4c06ef1ec1af46b0b6ab/work"
},
"Name": "overlay2"
},
其中overlay2文件系统是由码头工人图像和容器中使用。
在GraphDriver清单条目内，
是什么LowerDir/ MergedDir/ UpperDir/WorkDir说明什么？
回答没有帮助
s3存储桶的资源策略bucket1是：
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Deny",
"Principal": "*",
"Action": "s3:*",
"Resource": "arn:aws:s3:::bucket1/*",
"Condition": {
"Bool": {
"aws:SecureTransport": "false"
}
}
},
{
"Effect": "Deny",
"Principal": "*",
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::bucket1/*",
"Condition": {
"StringNotEquals": {
"s3:x-amz-server-side-encryption": "AES256"
}
}
},
{
"Effect": "Deny",
"Principal": "*",
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::bucket1/*",
"Condition": {
"Null": {
"s3:x-amz-server-side-encryption": "true"
}
}
}
]
}
IAM 政策是bucket1：
{
"Action": [
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::bucket1",
"arn:aws:s3:::bucket1/*"
],
"Effect": …在下面的 yaml 语法中：
readinessProbe:
httpGet:
path: /index.html
port: 80
initialDelaySeconds: 3
timeoutSeconds: 3
periodSeconds: 10
failureThreshold: 3
就绪探针在 Pod 的初始部署期间使用。
为了推出新版本的应用程序，使用滚动部署策略，是否使用就绪探针进行滚动部署？
path&port字段允许输入特定服务的 url 和端口号，但不能输入依赖服务。如何验证依赖服务是否也准备好？
如规范中所述，将切片转换为数组指针会生成指向切片底层数组的指针。
s := make([]byte, 2, 4)
s0 := (*[0]byte)(s) // s0 != nil
但编译器给出错误：cannot convert s (variable of type []byte) to *[0]byte
因为
frame.setVisible(false);
给出以下例外,
Exception in thread "main" java.lang.NullPointerException
at Simulation.drawOcean(Simulation.java:72)
at Simulation.main(Simulation.java:191)
应用程序有2个以下的java文件.
模拟类启动GUI.
在使用默认命令行参数运行Simulation.java之后,尽管有限的while循环,Frame仍未关闭.在模拟完成后,我无法通过单击关闭按钮(右上角 - 红色)关闭框架.
我需要为Frame设置一些属性吗？
请帮我!!!
/* Simulation.java */
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.util.Random;
/* DO NOT CHANGE THIS FILE (except as noted). */
/* (You may wish to make temporary changes or insert println() statements) */
/* while testing your code. When you're finished testing and debugging, */
/* though, make sure your code works with the …欧几里得的定义说，
\n\n\n\n\n给定两个整数 a 和 b，且 b \xe2\x89\xa0 0，存在唯一整数 q 和 r，使得 a = bq + r 且 0 \xe2\x89\xa4 r < |b|，其中 |b| 表示b的绝对值。
\n
根据以下观察，
\n\n>>> -3 % -2 # Ideally it should be (-2 * 2) + 1\n-1\n>>> -3 % 2 # this looks fine, (-2 * 2) + 1 \n1\n>>> 2 % -3 # Ideally it should be (-3 * 0) + 2\n-1\n看起来%运营商正在按照不同的规则运行。
此语音气泡用于在表单验证时显示错误消息
p.speech {
position: relative;
width: 200px;
height: 40px;
left: 100px;
top: 100px;
background-color: #FFFFFF;
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
border-radius: 10px;
text-align: center;
border: 1px solid red;
}
p.speech::before {
content: ' ';
position: absolute;
width: 0;
height: 0;
left: -10px;
top: -10px;
border: 20px solid;
border-color: #FF0000 transparent transparent transparent;
-webkit-transform: rotate(25deg);
-moz-transform: rotate(25deg);
transform: rotate(25deg);
}
p.speech::after {
content: ' ';
position: absolute;
width: 0;
height: 0;
left: -9px;
top: -9px;
border: 19px solid;
border-color: #FFFFFF transparent transparent …在以下规则中：
{
"Condition": {
"StringLikeIfExists": {
"iam:PassedToService": "lambda.amazonaws.com"
}
},
"Action": [
"iam:PassRole"
],
"Resource": [
"arn:aws:iam::${AWS::AccountId}:role/some-role*"
],
"Effect": "Allow"
}
我们正在使用此规则来创建 SAM 模板（sam deploy）的云形成堆栈。SAM 模板具有 lambda 和 lambda 的自定义角色。
上面的规则我们到底在说什么？