From my own experience, OutOfMemoryError are often due to a "Collection" instance retaining all objects in Java Heap. We all have our recipe to deal with OOME. Mine is quite simple, I get the dominator tree view, and I go down all the levels as long as the retained heap is high. And I often found an API Collection instance as java.util.List, java.util.Set or java.util.Map.

This plugin provides a new view Collection tree

You can access it with this new action in toolbar:

This view is quite similar to the Dominator Tree For each object, you have its size if it's a Collection, retained heap and percentage of total heap used.

View uses default IClassSpecificNameResolver instances to display name as in the Dominator Tree. However "Collection" instances like java.util.List, java.util.Set or java.util.Map are displayed differently to show the refered field in the problematic class.

In example : You can see that field Collection values in class com.github.qlefevre.eclipse.mat.test.heapdump.BagB retains 37.81% of total heap. Instance java.util.HashSet has 63404 elements and retains 8.24 MB.

You can download a prepackaged version with eclipse-mat-easy plugin already installed : Windows(x86_64) Linux(x86_64)

Note for Memory Analyzer 1.7.0: you must disable "Eclipse Oxygen" update site before installing plugins otherwise your MAT installation will get broken.

To disable Eclipse Oxygen in MAT 1.7.0, perform the following:

1. Open MAT Settings
2. Open Install/Update, Available Software Sites
3. Uncheck Eclipse Oxygen
4. Click Ok

Use the following update repository to install the latest released version: http://github.com/qlefevre/eclipse-mat-easy/raw/master/com.github.qlefevre.eclipse.mat.easy.updatesite

To install Eclipse MAT Easy plugin, perform the following:

1. Open Help, Install New Software...
2. For MAT 1.7.0: in case you have not disabled Eclipse Oxygen update site, click Available Software Sites and disable Oxygen there
3. Click Add, it will open a Add Repository window
4. Type Eclipse MAT Easy update site to the Name field
5. Type http://github.com/qlefevre/eclipse-mat-easy/raw/master/com.github.qlefevre.eclipse.mat.easy.updatesite to the Location field
6. Click Ok
7. All the checkboxes can be left by default (Show only latest version, Group items by category, ...)
8. Check Eclipse MAT Easy ! category
9. Click Next (Available Software)
10. Click Next (Installation Details)
11. Accept License
12. Click Finish and restart MAT

The following update site can be used to get development builds: http://github.com/qlefevre/eclipse-mat-easy/raw/master/com.github.qlefevre.eclipse.mat.easy.updatesite

Package	Class	Type	Extract Size	Library
com.google.common.collect	ImmutableList	List	Yes	Guava
com.google.common.collect	ImmutableSet	Set	Yes	Guava
com.google.common.collect	EnumBiMap EnumHashBiMap HashBiMap ImmutableMap ImmutableSortedMap	Map	Yes	Guava
gnu.trove.map.hash	THashSet TLinkedHashSet	Set	Yes	Trove4J
gnu.trove.map.hash	THashMap	Map	Yes	Trove4J
java.util	ArrayList LinkedList Arrays$ArrayList	List	Yes	JDK
java.util	HashSet LinkedHashSet TreeSet	Set	Yes	JDK
java.util.concurrent	ConcurrentSkipListSet	Set	No	JDK
java.util	HashMap IdentityHashMap LinkedHashMap TreeMap WeakHashMap	Map	Yes	JDK
java.util.concurrent	ConcurrentHashMap ConcurrentSkipListMap	Map	No	JDK
org.apache.commons.collections.list org.apache.commons.collections4.list	CursorableLinkedList FixedSizeList GrowthList LazyList NodeCachingLinkedList PredicatedList SetUniqueList TransformedList TreeList UnmodifiableList	List	Yes	Apache Commons Collections
org.apache.commons.collections.set org.apache.commons.collections4.set	ListOrderedSet Unmodifiable UnmodifiableSortedSet	Set	Yes	Apache Commons Collections
org.apache.commons.collections.map org.apache.commons.collections4.map	DefaultedMap FixedSizeMap FixedSizeSortedMap Flat3Map HashedMap LazyMap LinkedMap ListOrderedMap LRUMap MultiValueMap PredicatedMap ReferenceIdentityMap TransformedMap UnmodifiableMap UnmodifiableOrderedMap UnmodifiableSortedMap	Map	Yes	Apache Commons Collections
org.apache.commons.collections.map org.apache.commons.collections4.map	StaticBucketMap	Map	No	Apache Commons Collections