Loop can be collapsed with Stream API

Reports loops which can be replaced with stream API calls using lambda expressions.

Such a replacement changes the style from imperative to more functional and makes the code more compact.

Example:

  boolean check(List<String> data) {
    for (String e : data) {
      String trimmed = e.trim();
      if (!trimmed.startsWith("xyz")) {
        return false;
      }
    }
    return true;
  }

After the quick-fix is applied:

  boolean check(List<String> data) {
    return data.stream().map(String::trim).allMatch(trimmed -> trimmed.startsWith("xyz"));
  }

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.

Convert2streamapi

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.

This inspection depends on the Java feature 'Stream and Optional API' which is available since Java 8.

Inspection options

Here you can find the description of settings available for the Loop can be collapsed with Stream API inspection, and the reference of their default values.

Warn if only 'forEach' replacement is available: Not selected
Warn if the loop is trivial: Not selected

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