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Exploring Memory Analysis Views
Exploring the Dominating Instances View
2 Click Dominating Instances
149
.
or
Right-click the selected row and select the Why Are These Live? option from
the list.
The Dominating Instances view appears.
Understanding the Dominating Instances View
The Dominating Instances view allows you to view the instances (referred to as
dominators) that are holding a specific set of instances in the heap and preventing them
from being garbage collected.
Dominators offer a different way of viewing heap data, based on reachability analysis. If
every path from roots in the heap must pass through one instance (for example, a
Widget) before getting to another (for example, a String), the former is said to dominate
the latter (the Widget dominates the String).
During snapshot processing, JProbe analyzes the paths in the heap and identifies which
instances are reachable only through other instances. It builds a tree structure, called a
dominator tree, which starts with the roots of the heap and includes all instances in the
heap. Using the Dominating Instances view, you can analyze “why an instance is live”,
by navigating towards the roots of the tree.
The Dominating Instances view consists of three panes.