'Collection.toArray()' call style
Reports Collection.toArray() calls that are not in the preferred style, and suggests applying the preferred style.
There are two styles to convert a collection to an array:
A pre-sized array, for example,
c.toArray(new String[c.size()])An empty array, for example,
c.toArray(new String[0])
In older Java versions, using a pre-sized array was recommended, as the reflection call necessary to create an array of proper size was quite slow.
However, since late updates of OpenJDK 6, this call was intrinsified, making the performance of the empty array version the same, and sometimes even better, compared to the pre-sized version. Also, passing a pre-sized array is dangerous for a concurrent or synchronized collection as a data race is possible between the size and toArray calls. This may result in extra nulls at the end of the array if the collection was concurrently shrunk during the operation.
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.
ToArrayCallWithZeroLengthArrayArgument- 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.
Use the inspection options to select the preferred style.
Inspection options
Here you can find the description of settings available for the 'Collection.toArray()' call style inspection, and the reference of their default values.
- Prefer empty array
Default setting: Always
Other available settings:
According to language level
Never (prefer pre-sized array)
Availability
- By default bundled with
- Can be installed with plugin
Java, 241.18072