classloader

Java : in what order are static final fields initialized?

断了今生、忘了曾经 提交于 2019-11-27 04:45:07
Okay, so say I have a class that looks like this : public class SignupServlet extends HttpServlet { private static final Logger SERVLET_LOGGER=COMPANYLog.open(SignupServlet.class); private static final ExceptionMessageHandler handler = new ExceptionMessageHandler(); private static final SignupServletObservableAgent signupObservableAgent = new SignupServletObservableAgent(null, SERVLET_LOGGER); } Can I count on the class loader to initialize those fields in order, such that I can rely on SERVLET_LOGGER to be instantiated before signupObservableAgent? Laurence Gonsalves Yes, they are initialized

Java EE class loading standard

落爺英雄遲暮 提交于 2019-11-27 04:37:54
问题 WebSphere comes with parent last and parent first. Is this Java EE compliant? Is this supported by all application servers that are Java EE 5 compliant? 回答1: I did my own research (going through the specs and few blogs) and below is what I've figured EAR The spec DOES NOT define or mandate how the class loaders should work within an EAR. It however defines that there SHOULD be per thread context class loader for runtime loading of classes there MIGHT be a hierarchical class loading mechanism

Replacement System Classloader for Classes In Jars containing Jars

徘徊边缘 提交于 2019-11-27 04:32:27
So far, the examples I have seen for custom ClassLoaders involve subclassing the URLClassLoader, and using that specific instance to load classes in resources. I have tried in vain to look for alternative methods to replace the SystemClassLoader, so that my ClassLoader can be consulted for classes not located in the classpath. I tried Thread.currentThread().setContextClassLoader , but it doesn't seem to work. Is it even possible? Though this is an old question, there is indeed a way to replace the system ClassLoader. You might get more than you bargained for, however, with reflection. Field

sysLoader.getResource() problem in java

对着背影说爱祢 提交于 2019-11-27 03:43:50
问题 I am having following lines of code. sysLoader = (URLClassLoader)Thread.currentThread().getContextClassLoader(); url = sysLoader.getResource("tempFile.txt"); It is giving an weird problem. If I run this from a path where there is no space in the path (Folder names) then it is running fine. But if the path contains any spaces (line "c:\New Foler...") then it is not working. How to solve this? EDIT: In more detail - I inspected the sysloader object. sysloader -> UCP -> path Is having a path

Using javax.tools.ToolProvider from a custom classloader?

我与影子孤独终老i 提交于 2019-11-27 03:31:53
问题 It seems to be impossible to use javax.tools.ToolProvider from a custom classloader as required by Ant or Webstart: http://bugs.sun.com/view_bug.do?bug_id=6548428 javax.tools.ToolProvider.getSystemJavaCompiler() loads javax.tools.JavaCompiler into a URLClassLoader whose parent is the system classloader. The API does not seem to allow users to specify a parent classloader. How can one use javax.tools.JavaCompiler from a custom classloader? For example: Ant loads MyParserTask MyParserTask

How to use JPA2 on JBoss 5.x ? (or How to eliminate class loading isolation issue?)

佐手、 提交于 2019-11-27 03:28:34
问题 I would like JBoss to use only the dependencies located in my war file. Each time I deploy this war file, JBoss still uses its own jars. Here is the jboss-web.xml I use : <?xml version="1.0" encoding="UTF-8"?> <jboss-web> <class-loading java2ClassLoadingCompliance="false"> <loader-repository> my.package:loader=my-app.war <loader-repository-config> java2ParentDelegation=false </loader-repository-config> </loader-repository> </class-loading> </jboss-web> and the jboss-classloading.xml : <?xml

Load DEX file dynamically on Android 5.0

折月煮酒 提交于 2019-11-27 03:14:14
问题 Prior to Android 5.0 I was able to load DEX files dynamically using DexClassLoader and calling loadClass() method but with the latest Android version I get a ClassNotFoundException . Here is what I am doing: Generate DEX file. ../android-sdk/android-sdk-linux_86/build-tools/21.1.1/dx --dex --output=bin/output.dex bin/output.jar Create a DexClassLoader. DexClassLoader cl = new DexClassLoader( dexFile.getAbsolutePath(), odexFile.getAbsolutePath(), null, mContext.getClassLoader()); Call cl

Difference between Loading a class using ClassLoader and Class.forName

廉价感情. 提交于 2019-11-27 03:06:28
Below are 2 code snippets The first one uses ClassLoader class to load a specified class ClassLoader cls = ClassLoader.getSystemClassLoader(); Class someClass = cls.loadClass("TargetClass"); The second one uses Class.forName() to load a specified class Class cls = Class.forName("TargetClass"); What is the difference between the above said approaches. Which one serves for which purpose? Quick answer (without code samples) With the explicit ClassLoader cls = <a ClassLoader>; approach you have the flexibility of loading the class from a ClassLoader that is not your default ClassLoader. In your

WAS 6.1 java.lang.VerifyError: class loading constraint violated

狂风中的少年 提交于 2019-11-27 02:02:10
问题 The environment is WAS 6.1 on Linux, deploying a webapp that uses classes from xercesImpl.jar. Due to company policy restrictions, the app must be deployed with settings: Class Loader Order Classes loaded with parent class loader first -> Classes loaded with application class loader first WAR class loader policy Class loader for each WAR file in application -> Single class loader for application The WAR file contains a copy of xercesImpl.jar, the same one that was in the classpath when the

Jython CLASSPATH, sys.path and JDBC drivers

可紊 提交于 2019-11-27 01:58:23
问题 How can I add JDBC drivers at runtime to Jython? Using CLASSPATH works, but using sys.path doesn't work with zxJDBC even though the class is imported fine and can be manipulated from the Jython interpreter prompt. Why does this work: $ CLASSPATH=/tmp/jtds\-1.2.5.jar ./jython *sys-package-mgr*: processing new jar, '/private/tmp/jtds-1.2.5.jar' Jython 2.5.1 (Release_2_5_1:6813, Sep 26 2009, 13:47:54) [Java HotSpot(TM) 64-Bit Server VM (Apple Inc.)] on java1.6.0_20 Type "help", "copyright",