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View Code? Open in Web Editor NEW这是一个成为更好的Java程序员的系列教程
这是一个成为更好的Java程序员的系列教程
md地址:bestJavaer/book-view/read-theArtOfJavaConcurrencyProgramming.md
具体链接title:2w字 + 40张图带你参透并发编程!
RT。计算机网络部分的链接都404了。感谢整理汇总!
Yes!
or
No!
Sorry! You can't translate from PC
“接口的实现比如实现接口的全部方法,否则必须定义为抽象类,这就是我们下面要说的内容”
“比如”=“必须”
add(new Integer[] {1, 3, 2}); // 传递数组
上面代码编译不过(java11),换成 new int[] {1, 3, 2}
就好了。
文章太乱了,小白不知道阅读顺序😢
Github的md文档没有目录,可不可以提供个在线阅读的版本
提出一个书写错误 Klass Pointer,应该是Class Pointer.
出处:master/java-concurrent/java-lock-status.md
相同点:1.都可以拥有抽象方法 2.都不能实例化
不同点:1.接口需要实现类用implements关键字实现,并且支持接口与接口的多继承,类与接口的多实现。抽象类需要子类用extend关键
字继承,只支持单继承。
2.接口只可以有常量,默认是public final static修饰。抽象类既可以有普通变量,也可以有常量。
3.接口jdk1.8支持了默认方法和静态方法,1.9支持了私有方法,其余都是抽象方法。抽象类可以有任意的方法。
4.接口没有构造器,抽象类有构造器但是不能实例化,只是为了供给子类创建对象使用。
5.接口不能有初始代码块,抽象类可以。
public class TreeMap<K,V>
extends AbstractMap<K,V>
implements NavigableMap<K,V>, Cloneable, java.io.Serializable
{
/**
* The comparator used to maintain order in this tree map, or
* null if it uses the natural ordering of its keys.
*
* @serial
*/
@SuppressWarnings("serial") // Conditionally serializable
private final Comparator<? super K> comparator;
private transient Entry<K,V> root;
/**
* The number of entries in the tree
*/
private transient int size = 0;
/**
* The number of structural modifications to the tree.
*/
private transient int modCount = 0;
}
问题位置(加粗):
SQL 的书写规范
多行注释很多人不知道,这种写法不用可以用来添加真正的溈,也可以用来注释代码,非常方便
SQL 性能优化技巧
一、参数是子查询时,使用 EXISTS 代替 IN
。。。。。。
现在我们要查出同时存在于两个表的员工,即田中和铃木
田中和铃木表中好像未出现
。。。。。。
三、能写在 WHERE 子句里的条件不要写在 HAVING 子句里
。。。。。。
1.使用 GROUP BY 子句进行聚合时会进行排序,如果事先通过 WHERE 子句能筛选出一部分行,能减轻排序的钢制
"JDK 动态代理和 GClib 动态代理、JDK 动态代理具体实现原理、CGLib 动态代理、两者对比。"
其中应该是CGlib。
Are you my reader ?i'm sorry , l will fix it
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发件人: "crisxuan/bestJavaer" @.>;
发送时间: 2021年7月16日(星期五) 上午7:33
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主题: Re: [crisxuan/bestJavaer] I can't read Text in English? Can you fix it? (#12)
Sorry 😞 but you don't fix it.
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Originally posted by @crisxuan in #12 (comment)
float 是单精度浮点型,占用 4 位,1 float = 32 bits,默认值是 0.0f;
double 是双精度浮点型,占用 8 位,1 double = 64 bits,默认值是 0.0d;
占4个字节和8个字节吧
java基础里面的
计算机入门系列的最后一篇《程序员需要了解的硬核知识之控制硬件》链接有误,点开变成了《程序员需要了解的硬核知识之磁盘》。
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