HPjmeter 4.3 User's Guide

Until the algorithm can show the data with confidence, the graphical confidence interval is displayed
as a gray bar showing only relative relationship.
How Memory Leak Detection Works
HPjmeter constantly monitors all open sessions and analyzes the heap size after each garbage
collection. It tries to detect a longtime, increasing trend in the heap sizes. If it determines that a
dependency exists between elapsed time and the heap size, and that the heap size is always
greater than a certain linear function of time, it calculates a potential memory leak rate.
The next figure shows the heap size after each garbage collection plotted over time, using the
standard Garbage Collectionsdisplay. The metrics show that as time passes, the lowest post-garbage
collection heap size increases, indicating that a growing area of heap is un-collectible.
Figure 86 Early Indicator of Possible Memory Leak Using Garbage Collections Visualizer
The uncollectible and retained memory eventually fills the heap, as shown in this Heap Monitor
display.
214 Understanding How HPjmeter Works