【0】README
0.1）本文旨在po出当我们follow open projects 的时候，遇到一些在open API中不存在（NoClassDefFoundError）的类时的解决方法；
【1】problem+solution：
1.1）problem：一般case下，我们是 从低version 到高version的剖析project，而低version 可能年代久远而没有了相应的api 类，而这时如果我们编译该程序就可能会出现 NoClassDefFoundError；
Attention）当然了，如果可以download到相应的 包含该低version 下的class文件，直接使用带有该class文件的open jar包即可，不用这么麻烦；
1.2）solution：上google or baidu ，download 相关类的源代码，然后再手动编译该源代码，注意要手动创建它所属的包；
1.3）看个荔枝：如遇到错误java.lang.NoClassDefFoundError: org/apache/naming/JndiPermission，解决方法如下：
step1）下载org/apache/naming/JndiPermission.java 源代码；step2）手动建立层级文件夹 org/apache/naming/，并将 JndiPermission.java 文件放进该dir；step3）javac 编译得到JndiPermission的class文件；（stage 1 over.）step4）将原有的open jar 包解压（如catalina.jar 解压为 catalina）；step5）将上述的class 文件放入到 解压后的文件目录下（注意其包名要对应）；step6）最后，再将上述文件夹打jar包（catalina -》 catalina.jar -》Bingo.）补充）打jar包命令：进入 catalina dir，jar cvf catalina.jar ./；
Attention）再次注意，能download带有低version class文件的open jar包再好不过，直接用它即可，如果不能download的话，可能就需要像本文这种比较麻烦的solution了；
【2】in following apache，我遇到的 NoClassDefFoundError 错误及其解决方法的console info 如下：
E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src>java -cp .;lib/servlet.jar;lib/catalina_4_1_24.jar;lib/catalina-5.5.4.jar;lib/naming-resources.jar;lib/naming-common.jar;lib/commons-collectio
ns.jar;lib/catalina.jar;E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\webroot com.tomcat.chapter8.startup.Bootstrap
HttpConnector Opening server socket on all host IP addresses
HttpConnector[8080] Starting background thread
WebappLoader[/myApp]: Deploying class repositories to work directory E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src\work\_\_\myApp
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/catalina/loader/Extensionat org.apache.catalina.loader.WebappClassLoader.findAvailable(WebappClassLoader.java:744)at org.apache.catalina.loader.WebappLoader.validatePackages(WebappLoader.java:1284)at org.apache.catalina.loader.WebappLoader.start(WebappLoader.java:682)at org.apache.catalina.core.StandardContext.start(StandardContext.java:3530)at com.tomcat.chapter8.startup.Bootstrap.main(Bootstrap.java:69)
Caused by: java.lang.ClassNotFoundException: org.apache.catalina.loader.Extensionat java.net.URLClassLoader.findClass(Unknown Source)at java.lang.ClassLoader.loadClass(Unknown Source)at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)at java.lang.ClassLoader.loadClass(Unknown Source)... 5 moreE:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src>java -cp .;lib/servlet.jar;lib/catalina_4_1_24.jar;lib/catalina-5.5.4.jar;lib/naming-resources.jar;lib/naming-common.jar;lib/commons-collectio
ns.jar;lib/catalina.jar;E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\webroot com.tomcat.chapter8.startup.Bootstrap
HttpConnector Opening server socket on all host IP addresses
HttpConnector[8080] Starting background thread
WebappLoader[/myApp]: Deploying class repositories to work directory E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src\work\_\_\myApp
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/catalina/loader/Extensionat org.apache.catalina.loader.WebappClassLoader.findAvailable(WebappClassLoader.java:744)at org.apache.catalina.loader.WebappLoader.validatePackages(WebappLoader.java:1284)at org.apache.catalina.loader.WebappLoader.start(WebappLoader.java:682)at org.apache.catalina.core.StandardContext.start(StandardContext.java:3530)at com.tomcat.chapter8.startup.Bootstrap.main(Bootstrap.java:69)
Caused by: java.lang.ClassNotFoundException: org.apache.catalina.loader.Extensionat java.net.URLClassLoader.findClass(Unknown Source)at java.lang.ClassLoader.loadClass(Unknown Source)at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)at java.lang.ClassLoader.loadClass(Unknown Source)... 5 moreE:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src>java -cp .;lib/servlet.jar;lib/catalina_4_1_24.jar;lib/catalina-5.5.4.jar;lib/naming-resources.jar;lib/naming-common.jar;lib/commons-collectio
ns.jar;lib/catalina.jar;E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\webroot com.tomcat.chapter8.startup.Bootstrap
HttpConnector Opening server socket on all host IP addresses
HttpConnector[8080] Starting background thread
LifecycleException: start: : java.lang.NoClassDefFoundError: org/apache/naming/JndiPermissionat org.apache.catalina.loader.WebappLoader.start(WebappLoader.java:678)at org.apache.catalina.core.StandardContext.start(StandardContext.java:3530)at com.tomcat.chapter8.startup.Bootstrap.main(Bootstrap.java:69)E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src>java -cp .;lib/servlet.jar;lib/catalina_4_1_24.jar;lib/catalina-5.5.4.jar;lib/naming-resources.jar;lib/naming-common.jar;lib/commons-collectio
ns.jar;lib/catalina.jar;E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\webroot com.tomcat.chapter8.startup.Bootstrap
HttpConnector Opening server socket on all host IP addresses
HttpConnector[8080] Starting background thread
WebappLoader[/myApp]: Deploying class repositories to work directory E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src\work\_\_\myApp
Starting Wrapper Primitive
Starting Wrapper Modern
StandardManager[/myApp]: Seeding random number generator class java.security.SecureRandom
StandardManager[/myApp]: Seeding of random number generator has been completed
Resources' docBase: E:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src\myAppStopping wrapper Primitive
Stopping wrapper ModernE:\bench-cluster\cloud-data-preprocess\HowTomcatWorks\src>
载入器)
Session管理)
HttpConnector.initialize() 和 start() 方法 以及 StandardContext.start()方法的分析)
安全性)
