add line to catalina.sh or catalina.bat:
export CATALINA_OPTS=”-Xms512M -Xmx1024M”
a) The -Xmx argument defines the max memory size that the heap can reach for the JVM. A low value can cause OutOfMemoryExceptions or a very poor performance if your program’s heap memory is reaching the maximum heap size. b) The -Xms argument sets the initial heap memory size for the JVM. This means that when you start your program the JVM will allocate this amount of memory instantly.