Specifying Heap Size Values

java ... -XX:NewSize=128m -XX:MaxNewSize=128m -XX:SurvivorRatio=8
-Xms512m -Xmx512m 

The default size for these values is measured in bytes. Append the letter `k' or `K' to the value to indicate kilobytes, `m' or `M' to indicate megabytes, and `g' or `G' to indicate gigabytes.

About Generational GC
JVM heap size
Heap Size
Heap Size Options
Heap Size
OutOfMemoryExeception