You may see errors such as the following when you try to run Java:
$ java Error occurred during initialization of VM Could not reserve enough space for object heap Error: Could not create the Java Virtual Machine. Error: A fatal exception has occurred. Program will exit.
This is due to the default Maximum Heap Size in java being 32GB and the JHPCE cluster defaults for mem_free, your h_vmem being set to 2GB and 3GB respectively. The default settings for qrsh would be too small to accommodate the memory required by Java. You have 3 options to get this to work.
1) If you think you will really need 32GB of memory for your java program, you can increase your mem_free and h_vmem settings of your qrsh command:
jhpce01: qrsh -l mem_free=40G,h_vmem=40G compute-085: java
2) More likely, you do not need 32GB for your Java program, so you can direct Java to use less memory by using the “-Xmx” and “-Xms” options to Java. For instance, if you want to set the initial heap size to 1GB and the maximum heap size to 2GB you could use:
jhpce01: qrsh compute-085: java -Xms1g -Xmx2g
3) An alternative way to set the Java memory settings is to use the “_JAVA_OPTIONS” environment variable. This is useful if the call to run java is embedded within a script that cannot be altered. For instance, if you want to set the initial heap size to 1GB and the maximum heap size to 2GB you could use:
jhpce01: qrsh compute-085: export _JAVA_OPTIONS="-Xms1g -Xmx2g" compute-085: java