最近公司让我帮忙部署一个环境，应用服务器用的tomcat，在启动时报如下错误：
信息: Deploying web application directory chongYiDa
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:303)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:431)
Caused by: java.lang.OutOfMemoryError: PermGen space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2820)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1143)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1638)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1516)
at org.apache.catalina.startup.ContextConfig.checkHandlesTypes(ContextConfig.java:1937)
at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:1900)
at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1787)
at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1746)
at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1732)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1237)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:866)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:316)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:89)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4900)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:140)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:812)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:787)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:570)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1010)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:933)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:468)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1267)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:308)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:89)
at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:328)
at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:308)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1043)
原因解析：
加载时用了大量的反射，动态代理
PermGen space的全称是Permanent Generation space,是指内存的永久保存区域,这块内存主要是被JVM存放Class和Meta信息的,Class在被Loader时就会被放到PermGen space中,它和存放类实例(Instance)的Heap区域不同,GC(Garbage Collection)不会在主程序运行期对PermGen space进行清理，所以如果你的应用中有很多CLASS的话,就很可能出现PermGen space错误,这种错误常见在web服务器对JSP进行pre compile的时候。如果你的WEB APP下都用了大量的第三方jar, 其大小超过了jvm默认的大小(4M)那么就会产生此错误信息了。
解决办法：在catalina.bat第二行添加
@echo off
set JAVA_OPTS=-server -Xms256m -Xmx512m -XX:PermSize=512M -XX:MaxPermSize=1024M