Ubuntu 12.04 系统下设置Tomcat 7服务器上JVM的内存大小

以前都是正常的Tomcat 7服务器，在增加了一个新工程后，无法正常访问，查看日志：

$ cat /var/log/tomcat7/catalina.out

可以看到如下错误信息：

SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Java heap space
        at java.util.concurrent.FutureTask.report(FutureTask.java:122)
        at java.util.concurrent.FutureTask.get(FutureTask.java:188)
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1128)
        at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:782)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1566)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1556)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.OutOfMemoryError: Java heap space
        at java.util.zip.InflaterInputStream.<init>(InflaterInputStream.java:88)
        at java.util.zip.ZipFile$ZipFileInflaterInputStream.<init>(ZipFile.java:389)
        at java.util.zip.ZipFile.getInputStream(ZipFile.java:370)
        at java.util.jar.JarFile.getInputStream(JarFile.java:412)
        at org.apache.tomcat.util.scan.FileUrlJar.getEntryInputStream(FileUrlJar.java:96)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1922)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1891)
        at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1877)
        at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1270)
        at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:855)
        at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:345)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
        at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5161)
        ... 7 more

说明Tomcat在增加新工程后，内存不足了。

解决方法如下：

修改/etc/default/tomcat7文件:

$ sudo vim /etc/default/tomcat7

找到如下信息：

# The home directory of the Java development kit (JDK). You need at least
# JDK version 1.5. If JAVA_HOME is not set, some common directories for
# OpenJDK, the Sun JDK, and various J2SE 1.5 versions are tried.
#JAVA_HOME=/usr/lib/jvm/openjdk-6-jdk

# You may pass JVM startup parameters to Java here. If unset, the default
# options will be: -Djava.awt.headless=true -Xmx128m -XX:+UseConcMarkSweepGC
#
# Use "-XX:+UseConcMarkSweepGC" to enable the CMS garbage collector (improved
# response time). If you use that option and you run Tomcat on a machine with
# exactly one CPU chip that contains one or two cores, you should also add
# the "-XX:+CMSIncrementalMode" option.
JAVA_OPTS="-Djava.awt.headless=true -Xmx128m -XX:+UseConcMarkSweepGC"

可以看到，目前限制的内存最大值为128MB，-Xmx128m，调整到256MB后重启Tomcat7。

$ sudo service tomcat7 restart

解决问题。