OSGi的类加载问题

Question

我使用了来自Maven回购的log4j-1.2.17捆绑包。我尝试在捆绑软件中执行此代码（我的捆绑软件调用了log4j-1.2.17捆绑软件）

    PropertyConfigurator.configure(props());
private static Properties props() {
    Properties props = new Properties();
    props.put("log4j.rootLogger", "INFO, R");
    props.put("log4j.appender.R",
            "org.apache.log4j.DailyRollingFileAppender");
    props.put("log4j.appender.R.File", "logs/IhtikaClient.log");
    props.put("log4j.appender.R.Append", "true");
    props.put("log4j.appender.R.Threshold", "INFO");
    props.put("log4j.appender.R.DatePattern", "'.'yyyy-MM-dd");
    props.put("log4j.appender.R.layout", "org.apache.log4j.PatternLayout");
    props.put("log4j.appender.R.layout.ConversionPattern",
            //"%d{HH:mm:ss,SSS} %c - %m%n");
            //"[%5p] %d{yyyy-MM-dd mm:ss} (%F:%M:%L)%n%m%n%n");
            "[%5p] %d{yyyy-MM-dd mm:ss} %c (%F:%M:%L)%n%m%n");
    return props;
}

但是我有错误

log4j:ERROR A "org.apache.log4j.DailyRollingFileAppender" object is not assignable to a "org.apache.log4j.Appender" variable.
log4j:ERROR The class "org.apache.log4j.Appender" was loaded by 
log4j:ERROR [org.apache.felix.framework.BundleWiringImpl@9da1dd] whereas object of type 
log4j:ERROR "org.apache.log4j.DailyRollingFileAppender" was loaded by [sun.misc.Launcher$AppClassLoader@4b222f].
log4j:ERROR Could not instantiate appender named "R".
log4j:ERROR A "org.apache.log4j.DailyRollingFileAppender" object is not assignable to a "org.apache.log4j.Appender" variable.
log4j:ERROR The class "org.apache.log4j.Appender" was loaded by 
log4j:ERROR [org.apache.felix.framework.BundleWiringImpl@9da1dd] whereas object of type 
log4j:ERROR "org.apache.log4j.DailyRollingFileAppender" was loaded by [sun.misc.Launcher$AppClassLoader@4b222f].
log4j:ERROR Could not instantiate appender named "R".

捆绑包已按顺序加载

.getBundleContext().installBundle("......../log4j-1.2.17.jar")
.getBundleContext().installBundle("......../I_MainForm-1.0-SNAPSHOT.jar")

如何解决这个错误？拜托，对不起我的英语。最好的问候，亚瑟。

Answer 1

由于您的Log4j类似乎已由sun.misc类加载器加载，我认为某些东西正在从OSGi外部提供log4j类。有Log4J条目解释了为什么它无法加载Log4J类的事实意味着，已经存在某个版本的Log4J 。

您是否正在使用Felix的定制版本？如果可以，您能否找到带有org.osgi.framework.system.packages=...条目或org.osgi.framework.system.packages.extra=...条目的配置文件之类的东西？

如果仅删除Log4j捆绑包会怎样？还能找到Log4j类吗？