How to set up a really big JVM heap size?

Question

According to the JVM 6 documentation, server class machines receive by default an initial heap size as 1/4 RAM or 1GB. Considering our Solaris 64Bit server has 64 GB, the initial heap size will default in as 256MB. Therefore, I need to set manually the heap size using the XMX parameter for 4GB. Though, when I add "-Xmx4096M", Tomcat does not start. Here is the error message: ``` Invalid maximum heap size: -Xmx4096M The specified size exceeds the maximum representable size. Could not create the Java virtual machine. ``` What should be my command line parameters to allow my heap to grow up to 4GB?

Accepted Answer

Thanks for all your input, guys! Though, the output of my `java -version` mentions `mixed mode` which means that it is 64 bits. The real solution is adding `-d64` to force it to run in 64 bits and therefore allocate the 4GBs.

How to set up a really big JVM heap size?

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