Call to 'Arrays.asList()' with too few arguments

Reports calls to Arrays.asList() with at most one argument.

Such calls could be replaced with Collections.singletonList(), Collections.emptyList(), or List.of() on JDK 9 and later, which will save some memory.

In particular, Collections.emptyList() and List.of() with no arguments always return a shared instance, while Arrays.asList() with no arguments creates a new object every time it's called.

Note: the lists returned by Collections.singletonList() and List.of() are immutable, while the list returned Arrays.asList() allows calling the set() method. This may break the code in rare cases.

Example:

  List<String> empty = Arrays.asList();
  List<String> one = Arrays.asList("one");

After the quick-fix is applied:

  List<String> empty = Collections.emptyList();
  List<String> one = Collections.singletonList("one");

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.

ArraysAsListWithZeroOrOneArgument

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

Availability

By default bundled with: IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,
Can be installed with plugin: Java, 241.18072

Last modified: 18 June 2024