http://www.antapex.org/messages_java.txt http://www.jvmmonitor.org/index.html…

Three kinds of throwables Throwables Checked Recoverable checked exceptions Y Y runtime exceptions N N errors N N Principle Use checked exceptions for conditions from which the caller can reasonably be expected to recover. Code that parses the string…

invalid end header( bad central directory size) 异常描述 java.util.zip.ZipException: invalid END header (bad central directory size) at java.util.zip.ZipFile.open(Native Method) at java.util.zip.ZipFile.<init>(ZipFile.java:219) at java.util.zip.ZipFile.…

The ideal time to catch an error is at compile time, before you even try to run the program. However, not all errors can be detected at compile time. To create a robust system, each component must be robust. By providing a consistent error-reporting…

The beginning of this chapter introduced the idea of writing code that can be applied as generally as possible. To do this, we need ways to loosen the constraints on the types that our code works with, without losing the benefits of static type check…

Forget Guava: 5 Google Libraries Java Developers Should Know Published on 2016 7 13 Somenath PandaFollow If we would stop someone during an intense hackathon and ask her to name a popular and ask her to name a popular Google Java library, the answer…

<Effective Java>目录摘抄. 我知道这看起来很糟糕.当下,自己缺少实际操作,只能暂时摘抄下目录.随着,实践的增多,慢慢填充更多的示例. Chapter 2 Creating and Destroying Objects Consider static factory methods instead of constructors Consider a builder when faced with many constructor parameters Enforce the s…

String   Thus, when you create a toString( ) method, if the operations are simple ones that the compiler can figure out on its own, you can generally rely on the compiler to build the result in a reasonable fashion. But if looping is involved, you sh…

Chapter 9 Exceptions Item 57: Use exceptions only for exceptional conditions 这条item的意思就是,千万不要用exception来控制control flow的终止,比如: // Horrible abuse of exceptions. Don't ever do this! try { int i = 0; while(true) range[i++].climb(); } catch(ArrayIndexOutO…

Error Handling with Exceptions The ideal time to catch an error is at compile time, before you even try to run the program. The rest of the problems must be handled at run time through some formality that allows the originator of the error to pass ap…

有一句这样话:一个衡量Java设计师水平和开发团队纪律性的好方法就是读读他们应用程序里的异常处理代码. 本文主要讨论开发Java程序时,如何设计异常处理的代码,如何时抛异常,捕获到了怎么处理,而不是讲异常处理的机制和原理. 在我自己研究Java异常处理之前,我查过很多资料,翻过很多书藉,试过很多搜索引擎,换过很多英文和中文关键字,但是关于异常处理设计的文章实在太少,在我研究完Java异常处理之后,我面试过很多人,也问过很多老员工,极少碰到对Java异常有研究的人,看来研究这个主题的人很少,本文内…

依稀记得自己第一次编译*.java文件,第一次运行*.class文件.但是六七年过去了,现在运行java写的程序更多的是用tomcat这种web容器.最近有个小需求,写一个监控zookeeper集群的报警器,当发现集群中节点发生变化时,发出邮件和短信通知运维人员.如果这么一个功能也写成一个web项目放到tomcat里,就有些杀鸡用牛刀了.于是就写了一个jar项目,用 java -jar 运行.占用资源少不说,部署启动很简单,也不占用访问端口.但也遇到了很多问题,才发现自己对java命令还是一知半…

Hi guys, I am happy to tell you that I am moving to the open source world. And Java is the 1st language I have chosen for this migration. It's a nice chance to read some great books like "Effective Java 2nd Edition" and share the note for what I…

Agenda Three Categories Of Exceptions Exceptions Hierarchy try-catch-finally block The try-with-resources User-defined Exceptions The Throws/Throw Keywords Three Categories Of Exceptions There have various of reasons cause different exceptions during…

Previous sections have shown how to return HTTP responses and it is possible to return HTTP errors using the same mechanism. However, sometimes when programming in Java it is more natural to use exceptions for HTTP errors. The following example shows…

The Java programming language uses exceptions to handle errors and other exceptional events.An exception is an event that occurs during the execution of a program that disrupts the normal flow of instructions. Java Exception Handling Overview Excepti…

In this example we will create a simple Maven project which uses Hibersap to call a function in SAP and print the result to the command line. Download and install the SAP Java Connector Download SAP Java Connector 3 from http://service.sap.com/connec…

原文地址:https://dzone.com/articles/7-java-performance-metrics-to-watch-after-a-major-1 The Java performance metrics you need to follow for understanding how your application behaves in production. Unlike the days when software used to be shipped in boxe…

异常处理是 Java 开发中的一个重要部分,是为了处理任何错误状况,比如资源不可访问,非法输入,空输入等等.Java 提供了几个异常处理特性,以try,catch 和 finally 关键字的形式内建于语言自身之中.Java 编程语言也允许创建新的自定义异常,并通过使用 throw 和 throws关键字抛出它们.在Java编程中,Java 的异常处理不单单是知道语法这么简单,它必须遵循标准的 JDK 库,和处理错误和异常的开源代码. 这里我们将讨论一些关于异常处理的 Java 最佳实践.在我们…

正 文:   有的时候我们需要在PHP里调用JAVA平台封装好的jar包里的class类和方法,一般飘易推荐的做法是采用php-java-bridge做桥接,本文就来介绍一下大致的实现方法. 先简单说下php-java-bridge做桥接的实现原理: 先打开java的一个监听端口,php调用java的时候,将对应的方法调用转发到java的指定端口,由java执行后再将结果返回给php.这种模式是一种比较典型的代理模式,php在这里成为了一个代理转发器,把java的类调用转发给后端的java执行.…

在Java中,异常分为受检查的异常,与运行时异常. 两者都在异常类层次结构中.这类容易出选择题 考试你是否掌握了异常类并清楚哪些异常类必须捕获 下面的图展示了Java异常类的继承关系. 图1 粉红色的是受检查的异常(checked exceptions),其必须被 try{}catch语句块所捕获,或者在方法签名里通过throws子句声明.受检查的异常必须在编译时被捕捉处理,命名为 CHecked Exception 是因为Java编译器要进行检查,Java虚拟机也要进行检查,以确保这个规则得到…

reference from:http://www.programcreek.com/2013/10/top-10-questions-about-java-exceptions/ This article summarizes the top 10 frequently asked questions about Java exceptions. 1. Checked vs. Unchecked In brief, checked exceptions must be explicitly c…

异常描述 1.简介 为了全面了解"异常"的概念,先来分析一个实例.假定要编写一个Java程序,该程序读取用户输入的一行文本,并在终端显示该文本.这里是一个演示Java语言I/O功能的简答回显(echo)程序.如果认为代码一定能正常运行,则可以编写一下程序. import java.io.*; public class EchoDemo{ public static void main(String[] args){ System.out.println("Enter text…

// File Name : URLDemo.java import java.net.*; import java.io.*; public class URLDemo { public static void main(String [] args) { try { URL url = new URL("http://www.amrood.com/index.htm?language=en#j2se"); System.out.println("URL is "…

翻译人员: 铁锚 翻译日期: 2013年11月22日 原文链接: Java Exception Handling Example 本文中有两个示例, 第一个演示了所有调用其他方法的地方,都必须处理被调用函数抛出的异常.第二个示例演示了捕获父类异常也可以用来捕获子类异常. 1 调用函数必须处理被调用函数抛出的异常 下面是处理异常的一段代码,就如同所演示的那样,所有调用方法链上的方法都必须处理被调用者抛出的异常,或者自身也进行抛出异常的声明,或者捕捉并处理. public class excepti…

1.Implement a thread-safe (blocking) queue: Class Producer implements Runable{ Private final BlockingQueue queue; Producer (BlockingQueue q){queue=q;} Public void run(){ try{ while(true){queue.put(produce()); }catch(InterruptedException ex){…handle…}…

上下文处理器 上下文处理器可以返回一些数据,在全局模板中都可以使用,比如登录后的用户数据,在很多页面中都需要使用,那么我们就可以方在上下文处理器中,就没有必要在每个视图中返回这个对象了. 在settings.py.TEMPLATES.OPTIONS.context_processors中,有许多内置的上下文处理器,这些上下文处理器的作用如下: (1)django.template.context_processors.debug:增加一个debug和sql_queries变量,在模板中可以通过他…

封面:洛小汐 译者:潘潘 知彼知己,方能百战不殆. 前言 本文总结了有关Java异常的十大常见问题. 目录 检查型异常(checked) vs. 非检查型异常(Unchecked) 异常管理的最佳实践箴言 为什么在try代码块中声明的变量不能在catch或者finally中被引用? 为什么 Double.parseDouble(null) 和 Integer.parseInt(null) 抛出的异常不一样呢? Java中经常使用的运行时异常 我们可以在同一个catch子句中捕获多个异常吗? 在…

C++ Core Guidelines September 9, 2015 Editors: Bjarne Stroustrup Herb Sutter This document is a very early draft. It is inkorrekt, incompleat, and pµøoorly formatted. Had it been an open source (code) project, this would have been release 0.6. Copy…

Table of Contents 1. Solving typical Android development problems 1.1. Clean Project 1.2. android.content.ActivityNotFoundException 1.3. Problems with Android Debug Bridge (adb) 1.4. LogCat 1.5. Java7 1.6. Eclipse reports file from R.java as missing…