Object allocation in loop

Reports object or array allocations inside loops. While not necessarily a problem, an object allocation inside a loop is a great place to look for memory leaks and performance issues.

The inspection reports the following constructs:

Explicit allocations via new operator
Methods known to return new object
Instance-bound method references
Lambdas that capture variables or this reference

Example:

  // Explicit allocation
  for (Status status : Status.values()) {
    declarationsMap.put(status, new ArrayList<>());
  }

  // Lambda captures variable
  String message = "Engine running.";
  for (Engine engine : engines) {
      if (!isRunning(engine)) {
          logger.warn(() -> {
              return String.format(message);
          });
      }
  }

  // Instance-bound method reference
  for(Node node : nodes) {
    descriptor = node.getDescription();
    descriptor.ifPresent(dynamicTestExecutor::execute);
  }

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.

ObjectAllocationInLoop

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