Call to 'String.concat()' can be replaced with '+'

Reports calls to java.lang.String.concat().

Such calls can be replaced with the + operator for clarity and possible increased performance if the method was invoked on a constant with a constant argument.

Example:

  String foo(String name) {
    return name.concat("foo");
  }

After the quick-fix is applied:

  String foo(String name) {
    return name + "foo";
  }

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.

CallToStringConcatCanBeReplacedByOperator

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 | Code style issues

Inspection ID: CallToStringConcatCanBeReplacedByOperator

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 CallToStringConcatCanBeReplacedByOperator

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

IntelliJ IDEA 2025.3

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.3, Qodana for JVM 2025.3,

Last modified: 03 December 2025