This assumes you have analyzed a native_stderr.log in Garbage Collection and Memory Visualizer, and one of the tuning recommedations is:

"The mean occupancy is x%. This is high, so you may improve application performance by increasing your heap size. Increasing the heap size should reduce the garbage collection overhead from its current reproved level of x%."

This comes down to doing an analysis of the heap size to determine if the heap size should be changed.