JAVA_OPTS remote debug

谈JAVA_OPTS环境变量不起作用

最近在处理运行一个java应用时，老是出现java.lang.OutOfMemoryError: Java heap space.即时我在环境变量里设置了JAVA_OPTS -Xmx2048m还是报错。 

javaeye上搜索了一番，发现很多人都有这个疑问。经过Team Leader的指导，发现： 

1、JAVA_OPTS只对tomcat/weblogic等Web服务器中间件有效，以“java -cp [*.jar] test.Main”方式运行的不会去读取JAVA_OPTS. 

2、如果在运行java类，需要设置Heap Size的话，需要如下方式： 
java -Xmx2048m -jar test.jar 
或者java -Xmx1024m -cp douglas.jar com.douglas.Main 
3、如果是在Unix或者Aix服务器上，可以直接写下如下语句 
export JAVA_OPTS=-Xmx1024m -Djava.awt.headless=true 
java $JAVA_OPTS -cp douglas.jar com.douglas.Main 
或者vi test.sh文件，写下： 
#!/bin/sh 
classpath=./douglas.jar 
/usr/java5/bin/java -Xmx1024M -cp $classpath com.douglas.Main 
4、对于非Java语言(C++)调用Java代码，最好的方式是提供给操作员设置的页面，在申明JavaVM时，将JavaOPTS数值放置至JavaVM中。 

对于JVM设置，可以查考如下配置example： 

# Memory configuration JAVA_OPTS="-server" JAVA_OPTS="$JAVA_OPTS -Xms1280m" JAVA_OPTS="$JAVA_OPTS -Xmx1280m" JAVA_OPTS="$JAVA_OPTS -XX:NewSize=640m" JAVA_OPTS="$JAVA_OPTS -XX:MaxNewSize=640m" JAVA_OPTS="$JAVA_OPTS -XX:SurvivorRatio=5" JAVA_OPTS="$JAVA_OPTS -XX:TargetSurvivorRatio=90" JAVA_OPTS="$JAVA_OPTS -XX:MaxTenuringThreshold=12" JAVA_OPTS="$JAVA_OPTS -XX:+UseConcMarkSweepGC" JAVA_OPTS="$JAVA_OPTS -XX:+CMSIncrementalMode" JAVA_OPTS="$JAVA_OPTS -XX:+CMSIncrementalPacing" JAVA_OPTS="$JAVA_OPTS -XX:+CMSParallelRemarkEnabled" JAVA_OPTS="$JAVA_OPTS -XX:+UseParNewGC" JAVA_OPTS="$JAVA_OPTS -XX:PermSize=64m" JAVA_OPTS="$JAVA_OPTS -XX:MaxPermSize=64m" JAVA_OPTS="$JAVA_OPTS -XX:+UseTLAB" # Enable class unloading (needed with ConcMarkSweepGC JAVA_OPTS="$JAVA_OPTS -XX:+CMSClassUnloadingEnabled" JAVA_OPTS="$JAVA_OPTS -XX:+CMSPermGenSweepingEnabled" # debug and memory tweaks to avoid Hotspot Compiler Failure JAVA_OPTS="$JAVA_OPTS -XX:+PrintCompilation" JAVA_OPTS="$JAVA_OPTS -XX:CodeCacheMinimumFreeSpace=2M" JAVA_OPTS="$JAVA_OPTS -XX:ReservedCodeCacheSize=64M" JAVA_OPTS="$JAVA_OPTS -XX:CompileCommandFile=/my/portal/bin/hotspot_compiler" # Enable JMX Remote Monitoring JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote" JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.port=9000" JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.ssl=false" JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.password.file=/my/portal/bin/jmxremote.password" JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.access.file=/my/portal/bin/jmxremote.access" # turn on some debug for GC only print the distribution when doing tuning JAVA_OPTS="$JAVA_OPTS -verbose:gc" JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCTimeStamps" JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCDetails" #JAVA_OPTS="$JAVA_OPTS -XX:+PrintTenuringDistribution" JAVA_OPTS="$JAVA_OPTS -Xloggc:/my/portal/logs/portal/gc.log" # Enable remote debugging port JAVA_OPTS="$JAVA_OPTS -Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n"

原文章地址：http://hi.baidu.com/goglad/item/39f0529dca365ddb7a7f01ca