classloader

I'm loading classes using a custom class loader. For the most part, everything works, but sometimes when I load particularly complex projects/libraries, I get a strange bug: Exception in thread "main" java.lang.ClassCircularityError: org/apache/commons/codec/binary/Hex at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) at java.lang.ClassLoader.defineClass(ClassLoader.java:616) at java.lang.ClassLoader.defineClass(ClassLoader.java:466) at my.custom.class.Loader.loadClass(...) Looking at the Javadocs, I wouldn't expect defineClass

So I have a web app which I deploy / redeploy on a remote Tomcat server instance. Sometimes, the deploy and even redeploy (by redeploy I mean moving the ROOT.war through SFTP and leave Tomcat to actually redeploy it) work as expected, no issues whatsoever with the database connection. Unfortunately, other times, after redeploy, it just refuses to connect to the database, as apparently it doesn't recognize the MySQL driver anymore. The MySQL connector lib is inside Tomcat's lib folder, not package with the WAR. pom.xml: <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java<

Closed. This question is off-topic . It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . Is it possible to make my own Custom Class Loader In java. If Yes Then Please Guide me. Instead of class obfuscation I want to change in class file so that it cant be reversed by any tool You can use some obfuscation tools, like ProGuard. A self written ClassLoader, must be placed in a standard .class file, that the JVM can load it. And then you secure loader can be reverse engineered. Don't do it by yourself.

In an attempt to solve this problem , I built a (very) small project that is reproducing part of it. It is a NetBeans project using Glassfish v2.1.1 and OpenJpa-1.2.2. Globally, the goal is to be able to reload dynamically some business code (called 'tasks') without the need to (re)make a full deployment (eg via asadmin). In the project there are two of them: PersonTask and AddressTask which are simply accessing some data and printing them out. In order to do that, I've implemented a custom class loader that read the binary of class files and inject it via the defineClass method. Basically,

The article "Cracking Java byte-code encryption" ( javaworld.com/javaworld/javaqa/2003-05/01-qa-0509-jcrypt.html ) explains why class file encryption using a custom class loader is pointless, because at some point you always need to call defineClass(), which passes the class file to the JVM as an unencrypted byte array. However I've seen solutions where a slightly different approach is used; the class is decrypted by a native library and handed over to the JVM as a java.lang.Class instance through the findClass() method -- defineClass() is never called. Does that mean that these solutions do

I am running a program in com.me.X.jar . In an external com.me.Y.jar , I have a configuration file located at ' config/conf.txt ' in the root of the Jar. How can I access this configuration file programmatically from within Java? com.me.Y.jar is not currently loaded in memory and is composed of just non-code resources. jar files are just zip files. So google for an example how to read a zip file. Or have a look at the API ZipInputStream The easiest option for reading embedded resources is to use Class.getResource or Class.getResourceAsStream I can think of several ways to achieve this,

We have a java applet which is working OK in most client environments, primarily Windows 7, but recently we have been asked to support Ubuntu clients as well. The problem is that when the applet is fired up on the Ubuntu client (running Firefox and the natively installed "IcedTEA" Java VM 1.7.0_75) we get this exception: java.lang.VerifyError: Cannot inherit from final class at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:800) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader