Tomcat OutOfMemory after switching JVM

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http://serverfault.com – I have a Tomcat6 server running on Debian squeeze there are 4 webapps running on it, and an in-JVM ActiveMQ server. It has been running for about a year with the same memorysettings, with openjdk-6. Everything has worked dandy, no issues at all. Now, for various reasons, i need to try out Sun's JDK. So, I installed sun's jvm with standard apt-get apt-get install sun-java6-bin , and switched using update-java-alternatives -s java-6-sun However, when i start tomcat, i get outofmemory, the server won't even start! If i switch back to openJDK, all works fine again. I haven't had any memory (HowTos)