Private means this could only be seen within this class. Protected means "package private", this could be seen by subclasses and package members. | Class | Package | Subclass | Subclass | World | | |(same pkg)|(diff pkg)| ————————————+———————+——…

Java Modifiers(java修饰符): Like other languages, it is possible to modify classes, methods, etc., by using modifiers. There are two categories of modifiers(两类修饰): Access Modifiers(可访问): default, public , protected, private Non-access Modifiers(不可访问): f…

Part 1 http://techmytalk.com/2014/01/24/java-interview-reference-guide-part-1/ Posted on January 24, 2014 by Nitin Kumar JAVA Object Oriented Concepts Java in based on Object Oriented concepts, which permits higher level of abstraction to solve any p…

What is a reasonable order of Java modifiers (abstract, final, public, static, etc.)? http://stackoverflow.com/questions/16731240/what-is-a-reasonable-order-of-java-modifiers-abstract-final-public-static-e…

最近在学习使用Scala语言做项目,感觉这门语言实在是太优美了!作为一个本科数学.研究生机器学习专业的混合人才(哈哈),这门语言真的是满足了普通计算机编程(告诉计算机怎么做)和函数式编程(告诉计算机做什么)的所有幻想.学了半个多月,根本停不下来!先来做个总结: 语法简洁,往往比Java少至少一半的代码量.比如: 支持自动类型判断,可以省去很多类型标志. e.g.  val x = 2 用伴生对象来生成类,省去new的麻烦.e.g. val cat = Cat("Hello Ketty"…

一.需求:计算网页访问量前三名 import org.apache.spark.rdd.RDD import org.apache.spark.{SparkConf, SparkContext} /** * 需求:计算网页访问量前三名 * 用户:喜欢视频 直播 * 帮助企业做经营和决策 * * 看数据 */ object UrlCount { def main(args: Array[String]): Unit = { //1.加载数据 val conf:SparkConf = new Spa…

fields[j].set(obj, val); 报: Exception in thread "main" java.lang.IllegalAccessException: Class pers.hanchao.reflect.fields.ReflectFieldDemo can not access a member of class pers.hanchao.reflect.common.User with modifiers "private" at s…

当前需求: 利用反射获取某一属性值运行结果:java.lang.IllegalAccessException: Class com.example.demo.test.Reflect can not access a member of class com.example.demo.test.EvalNum with modifiers "private static"... 反射用到的Bean类: package com.example.demo.test; import java.…

field 或者 method 是 provate的 field.setAccessible(true); method.setAccessible(true); 有时候是因为 newinstance 方法,报这个错. 查看源码,构造方法是私有的,将构造方法执行setAccessible(true); Constructor Builder = as[i].getDeclaredConstructor(); Builder.setAccessible(true); addFieldMethod.…

前言: 最近公司正在进行业务组件化进程,其中的路由实现用到了Java的反射机制,既然用到了就想着好好学习总结一下,其实无论是之前的EventBus 2.x版本还是Retrofit.早期的View注解框架都或多或少的用到Java的反射机制.以下是自己使用反射的两个地方,感兴趣的同学可以看下:Android okHttp网络请求之Json解析,Android业务组件化之子模块SubModule的拆分以及它们之间的路由Router实现. 什么是Java反射机制? JAVA反射机制是在运行状态中,对于任…