Description:

Tomcat does not have the correct access rights set when first installed:
drwxr-xr-x 5 root root 4096 Sep 23 07:58 bin
drwxr-xr-x 6 root root 4096 Sep 23 07:57 common
drwxrwxr-x 3 root tomcat 4096 Sep 23 07:57 conf
drwxr-xr-x 2 root root 4096 Sep 23 07:57 logs
drwxr-xr-x 5 root root 4096 Sep 23 07:57 server
drwxr-xr-x 4 root root 4096 Sep 23 07:57 shared
drwxr-xr-x 2 root root 4096 Sep 23 07:57 temp
drwxr-xr-x 8 root root 4096 Sep 23 07:57 webapps <--- Should be root:tomcat
drwxrwxr-x 2 root tomcat 4096 Sep 23 07:57 work

Which means that tomcat is unable to explode war-files and will throw the following exception:

Sep 30, 2010 3:05:19 PM org.apache.catalina.startup.HostConfig deployWAR
INFO: Deploying web application archive mini-webapp-1.0.0-SNAPSHOT.war
Sep 30, 2010 3:05:19 PM org.apache.catalina.startup.ContextConfig init
SEVERE: Exception fixing docBase: {0}
java.io.FileNotFoundException: /opt/tomcat/webapps/mini-webapp-1.0.0-SNAPSHOT/META-INF/MANIFEST.MF (No such file or directory)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:179)
at java.io.FileOutputStream.<init>(FileOutputStream.java:131)
at org.apache.catalina.startup.ExpandWar.expand(ExpandWar.java:457)
at org.apache.catalina.startup.ExpandWar.expand(ExpandWar.java:173)
at org.apache.catalina.startup.ContextConfig.fixDocBase(ContextConfig.java:864)
at org.apache.catalina.startup.ContextConfig.init(ContextConfig.java:999)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:279)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
at org.apache.catalina.core.StandardContext.init(StandardContext.java:5095)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4024)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:760)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:740)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:544)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:884)
at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:737)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:498)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:301)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1306)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1570)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1579)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1559)
at java.lang.Thread.run(Thread.java:619)

Solution:

chown -hR root:tomcat /opt/tomcat/webapps/

Steps to reproduce:

pacman -S tomcat && export TOMCAT_JAVA_HOME=/opt/java && /etc/rc.d/tomcat start && sudo cp somewar.war /opt/tomcat/webapps