Which approach best prevents state leakage between Scenario Outline iterations?

Direct Answer

Use a Dependency Injection container configured for scenario scope (e.g., PicoContainer, Spring @ScenarioScoped or Guice fresh child injector). This creates a new instance of the state‑holding class for every row in the Examples table, guaranteeing isolation between iterations.

Likely Explanation

It is assumed that the DI container automatically provides a fresh bean for each scenario row; without such configuration, static or singleton objects would retain state across rows.

Confirmed Framework Behavior

• Each Examples row is executed as an independent scenario with its own lifecycle.
• The default DI scope is “scenario”, causing the container to instantiate a new bean for each row.
• Cucumber creates a new step‑definition class instance for every scenario, including each Scenario Outline iteration.
• Official documentation states that each scenario runs in isolation and a new instance of step definition classes is created for each scenario.

Steps to Verify Isolation

1. Create a feature file with a Scenario Outline and an Examples table containing at least three rows.
2. Define a simple POJO such as public class Counter { int value; }.
3. Inject the POJO via constructor in a step definition class.
4. Add a @Before hook that increments counter.value and logs it.
5. Run the feature and observe that the logged value is 1 for every row, confirming a fresh instance per iteration.
6. Repeat the test using a static int counter in the step definition to demonstrate state leakage when DI scope is not used.

Diagnostic Question

Are you using any static fields, singleton‑scoped beans, or externally managed objects (e.g., a shared WebDriver stored in a static variable) in your step definitions or support code? If yes, those objects will leak state unless explicitly reset in a @Before hook.