ClassNotFoundException oracle.i18n.util.LocaleMapper on tomcat TLD scanning. ojdbc7 maven dep (xmlparserv2-12.1.0.2.jar transitive) causes this error

问题

I am receiving an error when running my spring-boot application with embedded-tomcat (haven't tried with server tomcat yet).

java.lang.IllegalStateException: Tomcat 7 reflection failed
    at org.springframework.boot.context.embedded.tomcat.SkipPatternJarScanner.scan(SkipPatternJarScanner.java:77)
    at org.apache.catalina.startup.TldConfig.execute(TldConfig.java:271)
    at org.apache.catalina.startup.TldConfig.lifecycleEvent(TldConfig.java:590)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5522)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException: null
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.boot.context.embedded.tomcat.SkipPatternJarScanner.scan(SkipPatternJarScanner.java:73)
    ... 12 common frames omitted
Caused by: java.lang.NoClassDefFoundError: oracle/i18n/util/LocaleMapper
    at oracle.xml.parser.v2.XMLReader.setEncoding(XMLReader.java:980)
    at oracle.xml.parser.v2.XMLReader.checkXMLDecl(XMLReader.java:3284)
    at oracle.xml.parser.v2.XMLReader.pushXMLReader(XMLReader.java:570)
    at oracle.xml.parser.v2.XMLReader.pushXMLReader(XMLReader.java:274)
    at oracle.xml.parser.v2.XMLParser.parse(XMLParser.java:232)
    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1576)
    at org.apache.catalina.startup.TldConfig.tldScanStream(TldConfig.java:565)
    at org.apache.catalina.startup.TldConfig.tldScanJar(TldConfig.java:513)
    at org.apache.catalina.startup.TldConfig.access$200(TldConfig.java:61)
    at org.apache.catalina.startup.TldConfig$TldJarScannerCallback.scan(TldConfig.java:300)
    at org.apache.tomcat.util.scan.StandardJarScanner.process(StandardJarScanner.java:259)
    at org.apache.tomcat.util.scan.StandardJarScanner.scan(StandardJarScanner.java:221)
    ... 17 common frames omitted
Caused by: java.lang.ClassNotFoundException: oracle.i18n.util.LocaleMapper
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 29 common frames omitted

On further inspection, It appears as though the previous version of the orai18n.jar depended on by the ojdbc7 maven dep contained this class in vesion 11.2.0.3 but the newer (12.1.0.2) file does not contain it.

回答1:

It's a conflict with xmlparserv2. Try this :

    <dependency>
        <groupId>com.oracle.jdbc</groupId>
        <artifactId>ojdbc7</artifactId>
        <version>12.1.0.2</version>
        <exclusions>
            <exclusion>
                    <groupId>com.oracle.jdbc</groupId>
                    <artifactId>xmlparserv2</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

回答2:

After much hassle, I've found the root cause (Edit: Actually the better answer provided has a more appropriate cause/solution, see Serri's answer):

according to this bug comment in spring-boot The Oracle SaxParserFactory impl and the (later run into after solving the first) DocumentBuilderFactory implementations are picked up instead of the default xerces impls. Changing the implementation using the META-INF/services/<class-name> files solved the issue:

in my.jar:

and each file:

// javax.xml.parsers.DocumentBuilderFactory
com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl

// javax.xml.parsers.SAXParserFactory
com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl

This causes each service finder to resolve the default xerces implementation in the standard java library.

回答3:

In my case I had the Oracle Jars installed under $CATALINA_HOME/lib to be able to set up a JNDI DB connection in Tomcat, simply removing xmlparserv2.jar from the $CATALINA_HOME/lib directory resolved the problem.

来源：https://stackoverflow.com/questions/44916255/classnotfoundexception-oracle-i18n-util-localemapper-on-tomcat-tld-scanning-ojd