Not sure I understand the question, you have a 3rd party lib and you want it to use your classloader to load classes. If you’re lucky the third party lib uses the threads context classloader which you can set using Thread.currentThread().setContextClassLoader(myClassLoader), in the same thread you can access this classloader with Thread.currentThread().getContextClassLoader()… Another point, but … Read more
This is known by Sun/Oracle, their advice is to use URI objects which will remove the %20 characters: Instead of doing this: FileInputStream fis = new FileInputStream(url.getFile()); you can force any %-escaped characters to be decoded by first converting the URL to a URI, and then use the path component of the URI as the … Read more
Download a new version and rename it with the same name of the last Jar and then initialise the new Jar, creating a seamless update of the Jar within the JVM … Is it even possible to update a Jar whilst its running? The JAR file is not ‘running’, the JVM is running. Your JAR … Read more
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 { return forName0(className, … Read more
Answer : When a JVM starts up, a special chunk of machine code runs that loads the system classloader. This machine code is known as the Bootstrap / Primordial (or sometimes – Null) classloader. It is not a Java class at all, as are all other classloaders. The bootstrap classloader is platform specific machine instructions … Read more
The main cause for the java.lang.OutOfMemoryError: Metaspace is: either too many classes or too big classes being loaded to the Metaspace. If you want to recreate the problem use this code snippet: public class Metaspace { static javassist.ClassPool cp = javassist.ClassPool.getDefault(); public static void main(String[] args) throws Exception { for (int i = 0; ; … Read more
Yes, they are initialized in the order in which they appear in the source. You can read all of the gory details in The Java Language Specification, §12.4.2. See step 9, which reads: … execute either the class variable initializers and static initializers of the class, or the field initializers of the interface, in textual … Read more
I personally do not like the ServiceLoader under any circumstances. It’s slow and needlessly wasteful and there is little you can do to optimize it. I also find it a bit limited — you really have to go out of your way if you want to do more than search by type alone. xbean-finder’s ResourceFinder … Read more
I thought this question was already asked and answered! What is the difference between Class.getResource() and ClassLoader.getResource()? getClass().getResource() searches relative to the .class file while getClass().getClassLoader().getResource() searches relative to the classpath root. If there’s an SSCCE here, I don’t understand why it doesn’t 1) Show the directory organization in the .jar, and… 2) Take package … Read more
Today is your lucky day, as I had to solve this exact problem. I warn you though, the innards of class loading are a scary place. Doing this makes me think that the designers of Java never imagined that you might want to have a parent-last classloader. To use just supply a list of URLs … Read more