Gherkin Nested Steps meaning

I am writing Gherkin test cases and Java step definitions in my project. I am new to Gherkin and trying to understand the meaning of nested steps. Can you please help me to understand if the 2nd scenario given involves nested steps?

In my example, I would like to reuse 1st scenario code in 2nd scenario given statement logic. Is there a best way to reuse or rewrite the logic? Note: Below example is written just to explain my question. It may not be a good Gherkin.

Background:
    Given The application is opened

Scenario: Successful Login
    Given the user name and password are entered
    When login button is clicked
    Then user login is successful

Scenario: Add Address Successful
    Given user login is successful
    And Add Address button is clicked
    And user city, country are entered
    when Submit button is clicked

Nested steps refer to calling defined steps inside a "main" one. In your example, the first scenario has the login functionality, which will / can be used in all other scenarios that require the user to be logged in.

So, the second scenario will have a Given step which calls the login action / steps of the first scenario. There are multiple ways to do this:

1. If you are defining those steps in the same class, it's just a matter of calling the same methods inside a different step / method.

Like so:

public class TestStepsOne {

    // Steps from first scenario

    @Given("^the user name and password are entered$")
    public void enterUsernamePassword() throws Throwable {
        System.out.println("User and password entered");
    }

    @When("^login button is clicked$")
    public void clickLoginButton() throws Throwable {
        System.out.println("Clicked login button");
    }

    @Then("^user login is successful$")
    public void isLoggedIn() throws Throwable {
        System.out.println("Logged in!");
    }

    // All together

    @Given("the user is logged in")
    public void loginSuccessfully() throws Throwable {
        enterUsernamePassword();
        clickLoginButton();
        isLoggedIn();
    }
}

Now you can use the Given the user is logged in in any scenario, and it will perform the login action.

2. Using Picocontainer -> details here

First you need to add these dependencies to your pom.xml:

<dependency>
    <groupId>org.picocontainer</groupId>
    <artifactId>picocontainer</artifactId>
    <version>2.15</version>
</dependency>
<dependency>
    <groupId>info.cukes</groupId>
    <artifactId>cucumber-picocontainer</artifactId>
    <version>1.2.5</version>
</dependency>

You can separate your step definitions.

Like so:

public class TestStepsOne {

    // Same as above, without the nested one

}

and second class:

public class TestStepsTwo {
    private final TestStepsOne testStepsOne;

    public TestStepsTwo(TestStepsOne testStepsOne) {
        this.testStepsOne = testStepsOne;
    }

    @Given("the user is logged in")
    public void loginSuccessfully() throws Throwable {
        testStepsOne.enterUsernamePassword();
        testStepsOne.clickLoginButton();
        testStepsOne.isLoggedIn();
    }
}

3. Using cuke4duke -> details here , includes examples

Like so:

public class CallingSteps extends Steps {
    public CallingSteps(StepMother stepMother) {
        super(stepMother);
    }

    @When("^I call another step$")
    public void iCallAnotherStep() {
        Given("the user is logged in"); // This will call a step defined somewhere else.
    }
}

Hope this helps