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Java Concurrency Tutorial – Locking: Explicit locks


1. Introduction In many cases, using implicit locking is enough. Other times, we will need more complex functionalities. In such cases, java.util.concurrent.locks package provides us with lock objects. When it comes to memory synchronization, the internal mechanism of these locks is the same as with implicit locks. The difference is that explicit locks offer additional features. The main advantages or ...

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Value-Based Classes


In Java 8 some classes got a small note in Javadoc stating they are value-based classes. This includes a link to a short explanation and some limitations about what not to do with them. This is easily overlooked and if you do that, it will likely break your code in subtle ways in future Java releases. To prevent that I ...

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JMeter负载测试入门教程 – 终极指南


本教程是关于JMeter的。我们将会涉及到的要点如下: 我们会解释JMeter是用来干什么的。 JMeter是如何设计和实现的以及涉及到哪些技术。 如何正确的安装和配置它。 它的用户界面(UI)的基本功能。 详细介绍如何配置不同的测试计划。 展示如何分析它的输出结果。 最后我们会提到一些重要的最佳实践。 本文所提到的所有示例的配置和实现环境是: Java 8 update 0.20,Eclipse Luna 4.4, JMeter 2.11 和MySQL Community Server 5.6.21. 目录 1. 简介 2. 涉及到的技术 3. 本文主要讲些什么? 4. 安装 5. GUI 概述 6. 可用的请求类型 7. 测试计划和组件 7.1. 线程组 7.2. 取样器 7.3. 逻辑控制器 7.4. 监听器 7.5. 定时器 7.6. 断言 7.7. 配置元件 7.8. 前置处理器 7.9. 后置处理器 8. 测试计划元素的执行顺序 9. 启动/停止测试计划 10. Web (HTTP) 测试计划 11. 数据库测试计划入门 12. Junit测试计划 13. 录制HTTP测试 14. JMeter 插件 ...

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Hibernate locking patterns – How does OPTIMISTIC_FORCE_INCREMENT Lock Mode work


Introduction In my previous post, I explained how OPTIMISTIC Lock Mode works and how it can help us synchronize external entity state changes. In this post, we are going to unravel the OPTIMISTIC_FORCE_INCREMENT Lock Mode usage patterns. With LockModeType.OPTIMISTIC, the locked entity version is checked towards the end of the current running transaction, to make sure we don’t use a ...

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Java 8特性指南 – 终极手册 (PDF下载)


编者按:距离Java 8的发布已经有段时间了,就目前看来它的确是一个非常重要的版本。我们之前已经在JavaCodeGeeks发布了一系列专题文章,如玩转Java 8-Lambda表达式和并发,Java 8日期/时间API入门:LocalDateTime 以及 JDK8时代的抽象类vs.接口。同时我们也从其它来源处引用了15个必读的Java 8教程。当然,我们也对它的一些短板进行了验证,如Java 8的暗面。为了读者们更好的阅读体验,现在是时候整合所有Java 8的主要特性于一处了。一起来享受它吧!         目录 1. 简介 2. Java语言的新特性 2.1. Lambda表达式和函数式接口 2.2. 接口的默认方法和静态方法 2.3. 方法引用 2.4. 重复型注解 2.5. 更强大的类型推断 2.6. 扩展的注解支持 3. Java编译器的新特性 3.1. 参数名 4. Java类库的新特性 4.1. Optional 4.2. Streams 4.3. 日期/时间API (JSR 310) 4.4. Nashorn JavaScript引擎 4.5. Base64 4.6. 并行数组 4.7. 并发 5. 新的Java工具类New Java tools 5.1. Nashorn引擎: jjs ...

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Unit Test, System Test, Red Test, Green Test


We tend to categorize different types of tests according to what they cover. Unit tests cover small portions of code, usually a method or a class, while we mock the rest of their interaction. Integration tests cover several components in concert, and then mock the other boundaries. System tests and their bigger brothers, End-to-End tests cover more and more. Those ...

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The Joel Test Updated For Programmers


A while back—the year 2000 to be exact—Joel Spolsky wrote a blog post entitled: “The Joel Test: 12 Steps to Better Code.” Many software engineers and developers use this test for evaluating a company to determine if a company is a good company to work for. In fact, many software development organizations use the Joel Test as a sort of self-test ...

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Default methods and multiple inheritance


Recently Lukas JOOQ Eder posted and article about nested classes and their use. This is an interesting topic and his article is, as always, interesting and worth reading. There was only one slight statement I could not agree with and we had a brief reply chain leading to default method and why there can not be something like     ...

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OSGi Service Test Helper: ServiceRegistrationRule


OSGi Service Tests can be an efficient means to avoid problems related to dangling service references. As promised in my post about writing simple service contribution verifications, this time I introduce a JUnit rule that assists in testing interactions between components. OSGi Service Tests for Component Interaction Assume we have a service that notifies related observers bound according to the ...

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JPA Tutorial – The ULTIMATE Guide (PDF Download)


EDITORIAL NOTE: The Java Persistence API (JPA) is a Java programming language application programming interface specification that describes the management of relational data in applications using Java Platform, Standard Edition and Java Platform, Enterprise Edition. JPA has become the de-facto standard to write application code that interacts with Databases. For this reason we have provided an abundance of tutorials here ...

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