在使用webservice,mule esb等需要jaxb的项目里经常会出现 JAXB 2.0 API is being loaded from the bootstrap classloader这个错误，按照打出的信息Use the endorsed directory mechanism to place jaxb-api.jar in the bootstrap classloader. (See http://java.sun.com/j2se/1.5.0/docs/guide/standards/)去做，通常是解决不了问题的，该建议信息有两个问题导致不可行：
1. 不是下载jaxb-api.jar 而是下载jaxb-api-2.1.jar文件
2.不是把下载的这个jar文件放在sun网站给出的<java-home>/lib/endorsed 下，而是要自己试验确定应该放在哪个目录下：
确定放在哪个目录下的方法如下：
首先要看你的项目是java项目还是java web项目：
A, java项目直接打印System.out.println(System.getProperty("java.endorsed.dirs"));即是jaxb-api-2.1.jar应该放的目录。
B, java web 项目要用一个可以正常启动的web项目(当然没用到jaxb的web项目)，打印System.out.println(System.getProperty("java.endorsed.dirs"));即可，我的是java web项目，打出的是E:/tomcat6/common/endorsed
我把jaxb-api-2.1.jar放到E:/tomcat6/common/endorsed下后问题解决。
注：没有common/endorsed目录的，自己创建。
JAXB 2.0 API is being loaded from the bootstrap classloader
2010-05-11 16:55:13
JAXB 2.0 API is being loaded from the bootstrap classloader
在SSH jdk6.0 Tomcat6.0环境中使用CXF 运行时报如下错误
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.apache.cxf.wsdl.WSDLManager' defined in URL [jar:file:/E:/workSpace/T82A/WebRoot/WEB-INF/lib/cxf/cxf-2.1.3.jar!/META-INF/cxf/cxf.fixml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.apache.cxf.wsdl11.WSDLManagerImpl]: Constructor threw exception; nested exception is java.lang.LinkageError: JAXB 2.0 API is being loaded from the bootstrap classloader, but this RI (from jar:file:/E:/workSpace/T82A/WebRoot/WEB-INF/lib/cxf/jaxb-impl-2.1.7.jar!/com/sun/xml/bind/v2/model/impl/ModelBuilder.class) needs 2.1 API. Use the endorsed directory mechanism to place jaxb-api.jar in the bootstrap classloader. (See http://java.sun.com/j2se/1.5.0/docs/guide/standards/)
...
Caused by: java.lang.LinkageError: JAXB 2.0 API is being loaded from the bootstrap classloader, but this RI (from jar:file:/E:/workSpace/T82A/WebRoot/WEB-INF/lib/cxf/jaxb-impl-2.1.7.jar!/com/sun/xml/bind/v2/model/impl/ModelBuilder.class) needs 2.1 API. Use the endorsed directory mechanism to place jaxb-api.jar in the bootstrap classloader. (See http://java.sun.com/j2se/1.5.0/docs/guide/standards/)
...
按照网上看说，在jdk1.6.0_05\jre\lib\下新建endorsed文件夹，放入jaxb-api.jar还是没有效果，经过我的仔细阅读E文，纠正这个错误，如果是Tomcat 5.5,则新建文件路径为“Tomcat 5.5\common\endorsed”，如果是Tomcat 6.0，则新建路径为“Tomcat 6.0\endorsed”。不是在jdk1.6.0_05\jre\lib\