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 9-1 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.

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