Idempotent loop body

Reports loops whose second and all subsequent iterations do not produce any additional side effects other than the one produced by the first iteration, which can indicate a programming error.

Such loops may iterate only zero, one, or infinite number of times. If the infinite number of times case is unreachable, such a loop can be replaced with an if statement. Otherwise, there's a possibility that the program can get stuck.

Example:

    public void foo(String baseName, String names) {
        int suffix = 1;
        String name = baseName;
        while (names.contains(name)) {
            // error: suffix is not updated making loop body idempotent
            name = baseName + suffix;
        }
    }

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.

IdempotentLoopBody

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 | Control flow issues

New in 2018.1

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 IdempotentLoopBody

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

IntelliJ IDEA 2025.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.2, Qodana for JVM 2025.2,

Last modified: 18 September 2025