The allocation hot spot comparison is one of the memory comparisons. It is created by invoking the memory comparison wizard. For more information on snapshot comparisons, please see the snapshot comparison overview.

The wizard has the following additional steps: Select snapshots The allocation hot spot comparison compares two snapshot files. In this step, you select the first and the second snapshot file for the comparison. The combo boxes contain all snapshot files that have been added to the snapshot selector. The first and second snapshot files must be different. Class selection In this step, you choose for which class or package the comparison should be made. By default all classed are selected, you can restrict the class selection to a single class or a single package. View parameters In this steps you can select aggregation level, liveness mode and hot spot options, just as for the allocation hot spots view.

Each row in the allocation hot spot comparison has the following columns: the name of the allocation hot spot the size in the second snapshot file minus the size in the first snapshot file the allocations in the second snapshot file minus the allocations in the first snapshot file The second column incorporates a bidirectional bar chart. Increases are painted in red and to the right, while decreases are painted in green and to the left. In the view settings dialog you can choose whether you want this bar chart to display absolute changes or the percentage of the change. The other value is displayed in parentheses. This setting also determines how this column is sorted.

By default, only allocation hot spots that have changed from one snapshot file to the other are displayed. You can change this behavior in the view settings dialog.

At the bottom of the allocation hot spot comparison is a view filter selector that filters data for specific package or class names.