urlclassloader

Java example with ClassLoader

由 帅比萌擦擦* 提交于 2019-11-30 05:42:25
问题 I have small problem. I learn java SE and find class ClassLoader. I try to use it in below code: I am trying to use URLClassLoader to dynamically load a class at runtime. URLClassLoader urlcl = new URLClassLoader(new URL[] {new URL("file:///I:/Studia/PW/Sem6/_repozytorium/workspace/Test/testJavaLoader.jar")}); Class<?> classS = urlcl.loadClass("michal.collection.Stack"); for(Method field: classS.getMethods()) { System.out.println(field.getName()); } Object object = classS.newInstance();

运行java程序的时候出现Exception in thread \"main\" java.lang.UnsupportedClassVersionError:

由 余生长醉 提交于 2019-11-29 00:37:10
1 Exception in thread "main" java.lang.UnsupportedClassVersionError: com/test/inherited/InheritableSon : Unsupported major.minor version 52.0 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.defineClass(URLClassLoader.java:449) at java.net.URLClassLoader.access$100(URLClassLoader.java:71) at java.net.URLClassLoader$1.run(URLClassLoader.java:361) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security

Problem reloading a jar using URLClassLoader

由 被刻印的时光 ゝ 提交于 2019-11-28 19:32:14
I need to add plugin functionality to an existing application for certain parts of the application. I want to be able to add a jar at runtime and the application should be able to load a class from the jar without restarting the app. So far so good. I found some samples online using URLClassLoader and it works fine. I also wanted the ability to reload the same class when an updated version of the jar is available. I again found some samples and the key to achieving this as I understand is that I need to use a new classloader instance for each new load. I wrote some sample code but hit a

腾讯云大数据套件Hermes-MR索引插件使用总结

由 …衆ロ難τιáo~ 提交于 2019-11-28 11:52:48
版权声明：本文由王亮原创文章，转载请注明出处: 文章原文链接： https://www.qcloud.com/community/article/121 来源：腾云阁 https://www.qcloud.com/community Hermes是多维分析利器，使用步骤分为索引创建和数据分发两个步骤。 Hermes目前尚未集成到TBDS套件（3.0版本）中且外部有客户需要在自己部署的集群上使用Hermes组件，这里就遇到了Hermes与外部Hadoop集群的适配问题。 Hermes与某客户外部集群集成后，一次压测时（2T数据量，445604010行，477字段全索引）使用单机版的Hermes索引创建插件由于数据量过大，出现 Out of Memory 等异常现象导致索引插件程序崩溃，实际产生的数据索引量和实际数据量差距很大。基于以上考虑，数平提供了基于MR的索引创建插件，提升索引创建效率。 以下记录了基于hadoop2.2版本的MR索引插件和外部集群的适配过程。 一.集群相关组件版本 Hermes版本：hermes-2.1.0-1.x86_64 Hadoop集群版本：Hadoop 2.7.1.2.3.0.0-2557 Hermes-index-MR插件使用的Hadoop-common：hadoop-common-2.2.0.jar 二.Hermes-MR插件使用方法 1.需修改配置

Java 9, compatability issue with ClassLoader.getSystemClassLoader

由 两盒软妹~` 提交于 2019-11-27 23:10:44
The following code adds jar file to the build path, it works fine with Java 8. However, it throws exception with Java 9, the exception is related to the cast to URLClassLoader. Any ideas how this can be solved? an optimal solution will edit it to work with both Java 8 & 9. private static int AddtoBuildPath(File f) { try { URI u = f.toURI(); URLClassLoader urlClassLoader = (URLClassLoader) ClassLoader.getSystemClassLoader(); Class<URLClassLoader> urlClass = URLClassLoader.class; Method method = urlClass.getDeclaredMethod("addURL", URL.class); method.setAccessible(true); method.invoke

java.lang.ClassFormatError

由 寵の児 提交于 2019-11-27 13:07:31
版权声明：本文为博主原创文章，遵循 CC 4.0 by-sa 版权协议，转载请附上原文出处链接和本声明。 本文链接：https://blog.csdn.net/CodeFarmer_/article/details/80744661 --------------------- 版权声明：本文为CSDN博主「朱世良」的原创文章，遵循CC 4.0 by-sa版权协议，转载请附上原文出处链接及本声明。 原文链接：https://blog.csdn.net/CodeFarmer_/article/details/80744661 这个错误很奇怪，查了很久终于找到了，在这里整理一下： Caused by: java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file javax/persistence/GenerationType at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(Unknown Source) at java.lang.ClassLoader.defineClass(Unknown

Problem reloading a jar using URLClassLoader

由 谁说胖子不能爱 提交于 2019-11-27 12:23:41
问题 I need to add plugin functionality to an existing application for certain parts of the application. I want to be able to add a jar at runtime and the application should be able to load a class from the jar without restarting the app. So far so good. I found some samples online using URLClassLoader and it works fine. I also wanted the ability to reload the same class when an updated version of the jar is available. I again found some samples and the key to achieving this as I understand is

Java security: Sandboxing plugins loaded via URLClassLoader

由 倖福魔咒の 提交于 2019-11-27 11:28:25
Question summary: How do I modify the code below so that untrusted, dynamically-loaded code runs in a security sandbox while the rest of the application remains unrestricted? Why doesn't URLClassLoader just handle it like it says it does? EDIT: Updated to respond to Ani B. EDIT 2: Added updated PluginSecurityManager. My application has a plug-in mechanism where a third party can provide a JAR containing a class which implements a particular interface. Using URLClassLoader, I am able to load that class and instantiate it, no problem. Because the code is potentially untrusted, I need to prevent

Quartz定时任务(四)

由 孤者浪人 提交于 2019-11-27 08:03:26
1.测试用例 package com.ninemax.application.quartz.loader; import java.io.File; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; import java.net.URL; import java.net.URLClassLoader; import org.quartz.JobDetail; import com.ninemax.application.quartz.model.MyJob; /** * 利用JAVA反射调用定时任务 * * @author Darker * */ @SuppressWarnings("all") public class ClassLoaderTest { public static void main(String[] args) { // 读取指定JAR包 File jarFile= new File("E:/Worksapces2015/Vip/WebRoot/WEB-INF/lib/quartz-1.8.3.jar"); // 读取指定的类 File classFile= new File("E:

Add jar to classpath at runtime under java 9

由 China☆狼群 提交于 2019-11-27 05:05:51
Until java9 for adding external jar to classpath in runtime by programmatically everybody used: URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader(); Method method = URLClassLoader.class.getDeclaredMethod("addURL", new Class[]{URL.class}); method.invoke(sysloader, new Object[]{file.toURI().toURL()}); Now with java9 we have problem: Exception in thread "main" java.lang.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader URLClassLoader doesn't work anymore in Java 9. What to do now under jdk9
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