Inspectopedia 2025.2 Help

Collection without initial capacity

Reports attempts to instantiate a new Collection object without specifying an initial capacity.

If no initial capacity is specified, a default capacity is used, which will rarely be optimal. Failing to specify initial capacities for collections may result in performance issues if space needs to be reallocated and memory copied when the initial capacity is exceeded. This inspection checks allocations of classes listed in the inspection's settings.

Example:

new HashMap<String, String>();

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

CollectionWithoutInitialCapacity
Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Java | Performance

Use the following options to configure the inspection:

  • List collection classes that should be checked.

  • Whether to ignore field initializers.

Inspection options

Here you can find the description of settings available for the Collection without initial capacity inspection, and the reference of their default values.

Classes to check

Default value:

[java.util.ArrayDeque, java.util.ArrayList, java.util.BitSet, java.util.HashMap, java.util.HashSet, java.util.Hashtable, java.util.IdentityHashMap, java.util.LinkedHashMap, java.util.LinkedHashSet, java.util.PriorityQueue, java.util.Vector, java.util.WeakHashMap, java.util.concurrent.ConcurrentHashMap, java.util.concurrent.PriorityBlockingQueue]
Don't report field initializers

Default value:

Not selected

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection CollectionWithoutInitialCapacity

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

Inspection Details

By default bundled with:

IntelliJ IDEA 2025.2, Qodana for JVM 2025.2,

Last modified: 18 September 2025