Beyond Java 8

Angie Jones

https://angiejones.tech

https://TestAutomationU.com

@techgirl1908

Java Champion
Senior Director, Developer Relations
Applitools & Test Automation University

image source: Hendrik Ebbers

@techgirl1908

@Test
public void accountsListed() {

    AccountsOverviewPage accountsOverviewPage =
            page.login(username, password);

    List<String> actualAccounts =
            accountsOverviewPage.getAccounts();

    List<Account> accounts = APIUtil.getAccounts(
    			Customers.getCustomerId(username));

    List<String> expectedAccounts = new ArrayList();
    for(Account account : accounts){
        expectedAccounts
                .add(String.valueOf(account.id()));
    }

    assertEquals(expectedAccounts, actualAccounts);
}

@techgirl1908

@Test
public void accountsListed() {

    AccountsOverviewPage accountsOverviewPage =
            page.login(username, password);

    List<String> actualAccounts =
            accountsOverviewPage.getAccounts();

    List<Account> accounts = APIUtil.getAccounts(
    			Customers.getCustomerId(username));

    List<String> expectedAccounts = new ArrayList();
    for(Account account : accounts){
        expectedAccounts
                .add(String.valueOf(account.id()));
    }

    assertEquals(expectedAccounts, actualAccounts);
}

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    List<String> actualAccounts =
            accountsOverviewPage.getAccounts();

    List<Account> accounts = APIUtil.getAccounts(
    			Customers.getCustomerId(username));

    List<String> expectedAccounts = new ArrayList();
    for(Account account : accounts){
        expectedAccounts
                .add(String.valueOf(account.id()));
    }

    assertEquals(expectedAccounts, actualAccounts);
}

TYPE INFERENCE FOR LOCAL VARIABLES

@techgirl1908

Java is still a statically typed language

@techgirl1908

Initialization is required

var accountsOverviewPage;

@techgirl1908

Only works for local variables

public class MyTests {
    var accountsOverviewPage = 
        page. login(username, password);
    
    @Test
    public void accountsListed() {}
}

@techgirl1908

Not allowed in headers

public class MyTests {
    
    public MyTests(var data){}
}

@techgirl1908

Naming is even more important now

var x = getX();

@techgirl1908

Everything doesn't need to be a var!

var numberOfAccounts = 5;

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();

    var accountsList =
            APIUtil.getAccounts(
               Customers.getCustomerId(username));

    var expectedAccountIdsList = new ArrayList<String>();
    for(var account : accountsList){
        expectedAccountIdsList
                .add(String.valueOf(account.id()));
    }

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

TYPE INFERENCE FOR LOCAL VARIABLES

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();

    var accountsList =
            APIUtil.getAccounts(
               Customers.getCustomerId(username));

    var expectedAccountIdsList = new ArrayList<String>();
    for(var account : accountsList){
        expectedAccountIdsList
                .add(String.valueOf(account.id()));
    }

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

@techgirl1908

public List<String> getAccounts(){

    List<WebElement> accountCells = 
         driver.findElements(accountColumn);
         
    List<String> accounts = new ArrayList();
    for(WebElement element : accountCells){
        accounts.add(element.getText());
    }
    return accounts;   
}

@techgirl1908

public List<String> getAccounts(){

    return driver.findElements(accountColumn)
            .stream()
            .map(WebElement::getText)
            .collect(Collectors.toList());
}

@techgirl1908

public List<String> getAccounts(){

    return driver.findElements(accountColumn)
            .stream()
            .map(WebElement::getText)
            .collect(Collectors.toList());
}

return driver.findElements(accountColumn)
            .stream()
            .map(e -> e.getText())
            .collect(Collectors.toList());

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();
            
    String customerId = Customers.getCustomerId(username);

    var expectedAccountIdsList =
        APIUtil.getAccounts(customerId)
          .stream()
          .map(Account::getId)
          .map(String::valueOf)
          .collect(Collectors.toList());

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

@techgirl1908

New line for

each method call

driver.findElements(accountColumn).stream().map(WebElement::getText).collect(Collectors.toList());

driver.findElements(accountColumn)
        .stream()
        .map(WebElement::getText)
        .collect(Collectors.toList());

@techgirl1908

var accountsList = APIUtil.getAccounts(customerId);
var checkingAccountsList = accountsList
        .stream()
        .takeWhile(account -> account.type().equals("CHECKING"))
        .collect(Collectors.toList());

takeWhile()

var accountsList = APIUtil.getAccounts(customerId);
var checkingAccountsList = accountsList
        .stream()
        .takeWhile(account -> account.type().equals("CHECKING"))
        .collect(Collectors.toList());

takeWhile()

var accountsList = APIUtil.getAccounts(customerId);
var checkingAccountsList = accountsList
        .stream()
        .dropWhile(account -> account.type().equals("CHECKING"))
        .collect(Collectors.toList());

dropWhile()

var accountsList = APIUtil.getAccounts(customerId);
var checkingAccountsList = accountsList
        .stream()
        .dropWhile(account -> account.type().equals("CHECKING"))
        .collect(Collectors.toList());

dropWhile()

Sort for deterministic results

var accountsList = APIUtil.getAccounts(customerId);

var checkingAccountsList = accountsList
        .stream()
        .sorted(Comparator.comparing(Account::type))
        .takeWhile(account -> account.type().equals("CHECKING"))
        .collect(Collectors.toList());

@techgirl1908

takeWhile() on sorted collection

dropWhile() on sorted collection

@techgirl1908

How does this differ from filter?

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();
            
    String customerId = Customers.getCustomerId(username);

	var expectedAccountIdsList =
           APIUtil.getAccounts(customerId)
            .stream()
            .map(Account::getId)
            .map(String::valueOf)
            .collect(Collectors.toList());

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

@techgirl1908

public static String getCustomerId(String name){

    String id;
    
    switch(name){
        case "john":
            id = "12212";
            break;
        case "mary":
            id = "4847474";
            break;
        case "tom":
            id =  "293743";
            break;
        default:
            id = "";
            break;
    }
    
    return id;
}

@techgirl1908

SWITCH EXPRESSIONS

@techgirl1908

public static String getCustomerId(String name) {

    String id = switch(name){
        case "john" -> "12212";
        case "mary" -> "4847474";
        case "tom" -> "293743";
        default    -> "";
    };
    
    return id;
}

public static String getCustomerId(String name){

    return switch(name){
        case "john" -> "12212";
        case "mary" -> "4847474";
        case "tom" -> "293743";
        default -> "";
    };
}

SWITCH EXPRESSIONS

@techgirl1908

public static String getCustomerId(String name) {
  return switch (name) {
    case "john": yield "12212";
    case "mary": yield "4847474";
    case "tom" : yield "293743";
    default    : yield "";
  };
}

SWITCH EXPRESSIONS

@techgirl1908

public static String getCustomerId(String name){

    return switch(name){
        case "john", "demo" -> "12212";
        case "mary" -> "4847474";
        case "tom" -> "293743";
        default -> "";
    };
}

SWITCH EXPRESSIONS

@techgirl1908

public static String getCustomerId(String name){

    return switch(name){
        case "john" -> {
            System.out.println("Hi John");
            yield "12212";
        }
        case "mary" -> "4847474";
        case "tom" -> "293743";
        default -> "";
    };
}

SWITCH EXPRESSIONS

@techgirl1908

Cannot mix and match -> and :yield

return switch(name){
    case "john" -> "12212";
    case "mary": yield "4847474";
    case "tom" -> "293743";
    default -> "";
};

@techgirl1908

Can throw Exceptions

return switch(name){
    case "john" -> "12212";
    case "mary" -> "4847474";
    case "tom" -> "293743";
    default -> throw new InvalidNameException();
};

@techgirl1908

When to use expressions vs statements?

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();
            
    String customerId = Customers.getCustomerId(username);

    var expectedAccountIdsList =
        APIUtil.getAccounts(customerId)
          .stream()
          .map(Account::getId)
          .map(String::valueOf)
          .collect(Collectors.toList());

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

@techgirl1908

public class APIUtil {

  public static List<Account> getAccounts(String customerId){
      return Arrays.asList(given()
          .header(new Header("Accept", "application/json"))
          .get(format(GET_ACCOUNTS, customerId))
          .as(Account[].class));
  }
}

@techgirl1908

[
  {
    "id": 13344,
    "customerId": 12212,
    "type": "CHECKING",
    "balance": 4022.93
  },
  {
    "id": 13455,
    "customerId": 12212,
    "type": "CHECKING",
    "balance": 1000
  }
]

@techgirl1908

public class Account {

    private int id;
    private int customerId;
    private String type;
    private double balance;

    public int getId() { return id; }
    public void setId(int id) { this.id = id; }

    public int getCustomerId() { return customerId; }
    public void setCustomerId(int customerId) { 
    	this.customerId = customerId; 
    }

    public String getType() { return type; }
    public void setType(String type) { this.type = type; }
    
    public double getBalance() { return balance; }
    public void setBalance(double balance) { 
    	this.balance = balance; 
    }
}

@techgirl1908

public record Account(
       int id,
       int customerId,
       String type,
       double balance){}

RECORDS

@techgirl1908

public record Account(
       int id,
       int customerId,
       String type,
       double balance
){
    @Override
    public String toString(){
        return "I've overriden this!";
    }
}

RECORDS

@techgirl1908

Records can be instantiated

Account account = new Account(
    13344, 12212, "CHECKING", 4033.93);

@techgirl1908

Records are immutable

Account account = new Account(
    13344, 12212, "CHECKING", 4033.93);
    
account.setType("SAVINGS");

@techgirl1908

Accessors don't start with get

Account account = new Account(
    13344, 12212, "CHECKING", 4033.93);
    
double balance = account.balance();

@techgirl1908

Inheritance is not supported.

record CheckingAccount() extends Accounts 
{
    
}

@techgirl1908

Records can implement interfaces

@techgirl1908

public interface AccountInterface {
    
    void someMethod();
}

public record Account(
        int id,
        int customerId,
        String type,
        double balance) implements AccountInterface
{
    public void someMethod(){
        
    }
}

@techgirl1908

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();
            
    String customerId = Customers.getCustomerId(username);

    var expectedAccountIdsList =
        APIUtil.getAccounts(customerId)
          .stream()
          .map(Account::getId)
          .map(String::valueOf)
          .collect(Collectors.toList());

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

@techgirl1908

[
  {
    "id": 13344,
    "customerId": 12212,
    "type": "CHECKING",
    "balance": 4022.93
  },
  {
    "id": 13455,
    "customerId": 12212,
    "type": "CHECKING",
    "balance": 1000
  }
]

@techgirl1908

String response = 
"[\n" +
"  {\n" +
    "    \"id\": 13344,\n" +
    "    \"customerId\": 12212,\n" +
    "    \"type\": \"CHECKING\",\n" +
    "    \"balance\": 4022.93\n" +
    "  },\n" +
    "  {\n" +
    "    \"id\": 13455,\n" +
    "    \"customerId\": 12212,\n" +
    "    \"type\": \"CHECKING\",\n" +
    "    \"balance\": 1000\n" +
    "  }\n" +
    "]";

@techgirl1908

public String getAccounts_mocked(){
    return """
            [
              {
                "id": 13344,
                "customerId": 12212,
                "type": "CHECKING",
                "balance": 3821.93
              },
              {
                "id": 13455,
                "customerId": 12212,
                "type": "LOAN",
                "balance": 989
              }
            ]
            """;
}

TEXT BLOCKS

@techgirl1908

Text cannot begin on

same line as """



System.out.println(""" Hey y'all! """);


System.out.println(""" 
                   Hey y'all!""");
                   

System.out.println(""" 
                   Hey y'all!
                   """);

@Test
public void accountsListed() {

    var accountsOverviewPage =
            page.login(username, password);

    var actualAccountIdsList =
            accountsOverviewPage.getAccounts();
            
    String customerId = Customers.getCustomerId(username);

    var expectedAccountIdsList =
        APIUtil.getAccounts(customerId)
          .stream()
          .map(Account::getId)
          .map(String::valueOf)
          .collect(Collectors.toList());

    assertEquals(expectedAccountIdsList, actualAccountIdsList);
}

@techgirl1908

public static List<String> getAccountIds_mocked(){
    return Arrays.asList("13344", "13455", "13566", "14010");
}

public static List<String> getAccountIds_mocked(){
    return List.of("13344", "13455", "13566", "14010");
}

COLLECTION CONVENIENCE METHOD

@techgirl1908

image source: Hendrik Ebbers

Map users = new HashMap();
users.put("john", 123);
users.put("alice", 456);
users.put("sue", 789);

Map users = Map.of("john", 123, "alice", 456, "sue", 789);

COLLECTION CONVENIENCE METHOD

@techgirl1908

The of() method creates immutable collections

@techgirl1908

Map users = Map.of(
   "john", 123, 
   "alice", 456, 
   "sue", 789);

users.put("bob", 000);

users.remove("alice");

COLLECTION CONVENIENCE METHOD

@techgirl1908

Thank you!

@techgirl1908

Beyond Java 8

Angie Jones

https://angiejones.tech

https://TestAutomationU.com

@techgirl1908

Java Champion Senior Director, Developer Relations Applitools & Test Automation University

Java is still a statically typed language

Initialization is required

Only works for local variables

Not allowed in headers

Naming is even more important now

Everything doesn't need to be a var!

New line for

each method call

Sort for deterministic results

How does this differ from filter?

Cannot mix and match -> and :yield

Can throw Exceptions

When to use expressions vs statements?

Records can be instantiated

Records are immutable

Accessors don't start with get

Inheritance is not supported.

Records can implement interfaces

Text cannot begin on

same line as """

The of() method creates immutable collections

Thank you!

Beyond Java 8

Angie Jones

https://angiejones.tech

https://TestAutomationU.com

@techgirl1908

Java Champion

Senior Director, Developer Relations

Applitools & Test Automation University

Java Champion
Senior Director, Developer Relations
Applitools & Test Automation University