classloader

I am so confused about these two class loaders. When talking about the hierarchy of Java class loaders, usually the bootstrap classloader and ext class loader and the third one (system classloader or app classloader) are mentioned. To be more accurate, I checked the source code of JDK. In class Launcher , there is the code: loader = AppClassLoader.getAppClassLoader(extcl); In class ClassLoader , the method: getSystemClassloader() Also says the system classloader is used to start the application. So which is the third one in the hierarchy, or are the two classloaders the same? Ravindra babu

So, every Java text book talks about how flexible Java is since it can load classes at run time. Just cobble together a string and give it to Class.forName() , and catch the ClassNotFoundException and handle it. So much for the theory. Can you give examples of how you've been using Java class loading to achieve a feature which otherwise wouldn't have been possible or easy? Note that I'm not asking "what great things could we do?" - I'm looking for real-world examples, be it an open-source application or - if you can describe this without giving out too much details - a proprietary application.

I have read a lot about the Java class loading process lately. Often I came across texts that claimed that it is not possible to add classes to the classpath during runtime and load them without class loader hackery (URLClassLoaders etc.) As far as I know classes are loaded dynamically. That means their bytecode representation is only loaded and transformed to a java.lang.Class object when needed. So shouldn't it be possible to add a JAR or *.class file to the classpath after the JVM started and load those classes, provided they haven't been loaded yet? (To be clear: In this case the classpath

What is implied by @CallerSensitive annotation above methods? For example,the annotation is present in getClassLoader method of Class @CallerSensitive public ClassLoader getClassLoader() { // } According to the JEP I linked to in the comments (also here ), A caller-sensitive method varies its behavior according to the class of its immediate caller. It discovers its caller’s class by invoking the sun.reflect.Reflection.getCallerClass method. If you look at the implementation of Class#forName(String) @CallerSensitive public static Class<?> forName(String className) throws ClassNotFoundException

When calling loadClass() on a ClassLoader , does the ClassLoader first check if the class has been loaded, or does it immediately delegate this check to its parent ClassLoader ? Java API says: When requested to find a class or resource, a ClassLoader instance will delegate the search for the class or resource to its parent class loader before attempting to find the class or resource itself. But there's a specific chapter about class loader in the book Java Reflection in Action that says: Class loader calls findLoadedClass to check if the class has been loaded already. If a class loader does

I've been reading code and documentation to try to understand how class reloading works in clojure. According to many websites, such as http://tutorials.jenkov.com/java-reflection/dynamic-class-loading-reloading.html , whenever you load a class essentially you obtain the bytecode (via any data mechanism), convert the bytecode into an instance of class Class (via defineClass), and then resolve (link) the class via resolveClass. (Does defineClass implicitly call resolveClass?). Any given classloader is only allowed to link a class once. If it attempts to link an existing class, it does nothing.

I have a code that load all classes in folder with same package name ( second ). how can i change it to load all classes in a folder with deference package (not in second ) (and we don't know the package name) int classCounter = 0; File folderAdded = new File("..//940424//second"); File [] classFileAdded = folderAdded.listFiles(); String [] addedClassName = new String [classFileAdded.length]; List<Operations> newOp = new ArrayList<Operations>(); Operations newOpTemp = null; for(int i = 0; classCounter < classFileAdded.length; classCounter++){ addedClassName [classCounter] = classFileAdded

Currently doing a typestate project and I am having problems with importing the List class. When I try to compile the class it throws an error in command line saying cannot find symbol and points to the List symbol. I was wondering how you fix this. It seems to work for String and Integer but not for List. The java file is automatically create via another program that translates .scr files. In the scr file I use the following line : type <java> "java.lang.List" from "rt.jar" as List; Java file: package demos.Redis; import java.io.BufferedReader; import java.io.IOException; import java.io