No Hate on Java 8, But 9–14 Reign Supreme

Beyond Java 8
Angie Jones
https://angiejones.tech
https://TestAutomationU.com
@techgirl1908
Principal Developer Advocate
Director, Test Automation University
Applitools, San Francisco, CA, USA

@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);
}
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@Test1
public void accountsListed() {2
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List<String> actualAccounts =7
accountsOverviewPage.getAccounts();8
9
List<Account> accounts = APIUtil.getAccounts(10
Customers.getCustomerId(username));11
12
List<String> expectedAccounts = new ArrayList();13
for(Account account : accounts){14
expectedAccounts15
.add(String.valueOf(account.id()));16
}17
18
assertEquals(expectedAccounts, actualAccounts);19
}20
@Test1
3
AccountsOverviewPage accountsOverviewPage =4
page.login(username, password);5
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expectedAccounts15
}17
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}20
@Test1
3
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expectedAccounts15
}17
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}20
@Test1
3
6
9
12
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expectedAccounts15
}17
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}20
@Test1
3
6
9
12
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expectedAccounts15
}17
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}20
expectedAccounts
@Test1
3
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12
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}17
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}20
@Test1
3
6
9
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expectedAccounts15
}17
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}20
@Test
expectedAccounts
}
}
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@techgirl1908

@Test1
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expectedAccounts15
}17
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}20
@techgirl1908

var accountsOverviewPage =
@Test1
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expectedAccounts15
}17
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}20
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 {
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

@Test1
3
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var actualAccountIdsList =7
9
var accountsList =10
APIUtil.getAccounts(11
13
var expectedAccountIdsList = new ArrayList<String>();14
for(var account : accountsList){15
expectedAccountIdsList16
}18
19
assertEquals(expectedAccountIdsList, actualAccountIdsList20
}21
var actualAccountIdsList =
@Test1
3
var accountsOverviewPage =4
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13
}18
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}21
var accountsList =
APIUtil.getAccounts(
@Test1
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}18
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}21
var expectedAccountIdsList = new ArrayList<String>();
@Test1
3
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13
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}18
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}21
for(var account : accountsList){
@Test1
3
6
9
13
15
}18
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}21
TYPE INFERENCE FOR LOCAL VARIABLES

@Test
var accountsList =
APIUtil.getAccounts(
var expectedAccountIdsList = new ArrayList<String>();
for(var account : accountsList){
expectedAccountIdsList
}
assertEquals(expectedAccountIdsList, actualAccountIdsList
}
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@Test1
3
6
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13
}18
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}21
@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;
}
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public List<String> getAccounts(){1
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List<String> accounts = new ArrayList();6
for(WebElement element : accountCells){7
accounts.add(element.getText());8
}9
return accounts;10
}11
2
List<WebElement> accountCells =3
driver.findElements(accountColumn);4
5
6
for(WebElement element : accountCells){7
accounts.add(element.getText());8
}9
return accounts;10
}11
}
2
List<WebElement> accountCells =3
driver.findElements(accountColumn);4
5
List<String> accounts = new ArrayList();6
7
8
9
return accounts;10
}11
}
return accounts;
}
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@techgirl1908

return driver.findElements(accountColumn)
.stream()
.map(WebElement::getText)
.collect(Collectors.toList());
}
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return driver.findElements(accountColumn)
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.stream()4
.map(WebElement::getText)5
.collect(Collectors.toList());6
}7
.stream()
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return driver.findElements(accountColumn)3
4
}7
2
.stream()4
5
}7
2
.stream()4
6
}7
@techgirl1908

2
.stream()4
5
}7
.map(e -> e.getText())
.stream()2
3
@techgirl1908

var expectedAccountIdsList =
APIUtil.getAccounts(customerId)
.stream()
.map(Account::getId)
.map(String::valueOf)
@Test1
3
6
9
String customerId = Customers.getCustomerId(username);10
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}20
@techgirl1908

New line for
each method call
driver.findElements(accountColumn).stream().map(WebElement::getText).collect(Collectors.toList());
driver.findElements(accountColumn)
.stream()
@techgirl1908

var accountsList = APIUtil.getAccounts(customerId);
var checkingAccountsList = accountsList
.stream()
.takeWhile(account -> account.type().equals("CHECKING"))
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var accountsList = APIUtil.getAccounts(customerId);1
var checkingAccountsList = accountsList2
.stream()3
4
takeWhile()

.stream()
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takeWhile()

.stream()
.dropWhile(account -> account.type().equals("CHECKING"))
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.dropWhile(account -> account.type().equals("CHECKING"))
.stream()3
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dropWhile()

Sort for
deterministic results
.stream()
.sorted(Comparator.comparing(Account::type))
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.sorted(Comparator.comparing(Account::type))
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.stream()4
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.takeWhile(account -> account.type().equals("CHECKING"))6
@techgirl1908

takeWhile() on sorted collection

dropWhile() on sorted collection
@techgirl1908

@Test
String customerId = Customers.getCustomerId(username);
.stream()
}
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@Test1
3
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var expectedAccountIdsList =12
APIUtil.getAccounts(customerId)13
.stream()14
.map(Account::getId)15
.map(String::valueOf)16
18
}20
@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;
}
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String id;
public static String getCustomerId(String name){1
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switch(name){5
case "john":6
id = "12212";7
break;8
case "mary":9
id = "4847474";10
break;11
case "tom":12
id = "293743";13
break;14
default:15
id = "";16
break;17
}18
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return id;20
}21
case "john":
id = "12212";
break;
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String id;3
4
switch(name){5
6
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case "mary":9
id = "4847474";10
break;11
case "tom":12
id = "293743";13
break;14
default:15
id = "";16
break;17
}18
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return id;20
}21
String id;
switch(name){
case "john":
id = "12212";
break;
case "mary":
id = "4847474";
break;
case "tom":
id = "293743";
break;
default:
id = "";
break;
}
return id;
}
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21 @techgirl1908

String id = switch(name){
case "john" -> "12212";
case "mary" -> "4847474";
case "tom" -> "293743";
default -> "";
};
return id;
}
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2
3
case "john" -> "12212";4
case "mary" -> "4847474";5
case "tom" -> "293743";6
default -> "";7
};8
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return id;10
}11
case "john" -> "12212";
2
String id = switch(name){3
4
case "mary" -> "4847474";5
case "tom" -> "293743";6
default -> "";7
};8
9
return id;10
}11
return id;
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case "john" -> "12212";4
case "mary" -> "4847474";5
case "tom" -> "293743";6
default -> "";7
};8
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10
}11
SWITCH EXPRESSIONS
@techgirl1908

return switch(name){
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3
case "john" -> "12212";4
case "mary" -> "4847474";5
case "tom" -> "293743";6
default -> "";7
};8
}9
case "john" -> "12212";
case "mary" -> "4847474";
case "tom" -> "293743";
default -> "";
2
return switch(name){3
4
5
6
7
};8
}9
SWITCH EXPRESSIONS
@techgirl1908

case "john": yield "12212";
case "mary": yield "4847474";
case "tom" : yield "293743";
default : yield "";
public static String getCustomerId(String name) {1
return switch (name) {2
3
4
5
6
};7
}8
public static String getCustomerId(String name) {
return switch (name) {
case "john": yield "12212";
case "tom" : yield "293743";
default : yield "";
};
}
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SWITCH EXPRESSIONS
@techgirl1908

case "john", "demo" -> "12212";
case "mary" -> "4847474";
case "tom" -> "293743";
default -> "";
};
}
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case "john", "demo" -> "12212";
2
4
case "mary" -> "4847474";5
case "tom" -> "293743";6
default -> "";7
};8
}9
SWITCH EXPRESSIONS
@techgirl1908

case "john" -> {
System.out.println("Hi John");
yield "12212";
}
case "mary" -> "4847474";
case "tom" -> "293743";
default -> "";
};
}
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case "john" -> {
yield "12212";
}
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4
5
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case "mary" -> "4847474";8
case "tom" -> "293743";9
default -> "";10
};11
}12
2
case "john" -> {4
5
yield "12212";6
}7
case "mary" -> "4847474";8
case "tom" -> "293743";9
default -> "";10
};11
}12
yield "12212";
2
case "john" -> {4
System.out.println("Hi John");5
6
}7
case "mary" -> "4847474";8
case "tom" -> "293743";9
default -> "";10
};11
}12
SWITCH EXPRESSIONS
@techgirl1908

Cannot mix and
match -> and :yield
case "john" -> "12212";
case "tom" -> "293743";
default -> "";
};
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@techgirl1908

Can throw
Exceptions
case "john" -> "12212";
case "mary" -> "4847474";
case "tom" -> "293743";
default -> throw new InvalidNameException();
};
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@techgirl1908

When to use
expressions vs
statements?
@techgirl1908

@Test
.stream()
}
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@Test1
3
6
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.stream()14
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}20
@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));
}
}
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.as(Account[].class));
public class APIUtil {1
2
public static List<Account> getAccounts(String customerId){3
return Arrays.asList(given()4
.header(new Header("Accept", "application/json"))5
.get(format(GET_ACCOUNTS, customerId))6
7
}8
}9
@techgirl1908

[
{
"id": 13344,
"customerId": 12212,
"type": "CHECKING",
"balance": 4022.93
},
{
"id": 13455,
"type": "CHECKING",
"balance": 1000
}
]
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@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;
}
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@techgirl1908

public record Account(
int id,
int customerId,
String type,
double balance){}
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public record Account(1
int id,2
int customerId,3
String type,4
double balance){}5
int id,
int customerId,
String type,
double balance){}
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3
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5
RECORDS
@techgirl1908

int id,
int customerId,
String type,
double balance
){
@Override
public String toString(){
return "I've overriden this!";
}
}
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){
@Override
public String toString(){
return "I've overriden this!";
}
}
int id,2
int customerId,3
String type,4
double balance5
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RECORDS
@techgirl1908

Records can be
instantiated
Account account = new Account(
13344, 12212, "CHECKING", 4033.93);
@techgirl1908

Records are
immutable
13344, 12212, "CHECKING", 4033.93);
account.setType("SAVINGS");
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@techgirl1908

Accessors don't start
with get
13344, 12212, "CHECKING", 4033.93);
double balance = account.balance();
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3
4 double balance = account.balance();
Account account = new Account(1
13344, 12212, "CHECKING", 4033.93);2
3
4
@techgirl1908

Still in preview
int id,
int customerId,
String type,
double balance){}
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5
@techgirl1908

Still in preview
@JsonProperty("id") int id,
@JsonProperty("customerId") int customerId,
@JsonProperty("type") String type,
@JsonProperty("balance") double balance){}
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@techgirl1908

String response =
"[n" +
" {n" +
" "id": 13344,n" +
" "customerId": 12212,n" +
" "type": "CHECKING",n" +
" "balance": 4022.93n" +
" },n" +
" {n" +
" "id": 13455,n" +
" "customerId": 12212,n" +
" "type": "CHECKING",n" +
" "balance": 1000n" +
" }n" +
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@techgirl1908

public String getAccounts_mocked(){
return """
[
{
"id": 13344,
"type": "CHECKING",
"balance": 3821.93
},
{
"id": 13455,
"type": "LOAN",
"balance": 989
}
]
""";
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"id": 13344,
"type": "CHECKING",
"balance": 3821.93
public String getAccounts_mocked(){1
return """2
[3
{4
5
6
7
8
},9
{10
"id": 13455,11
"customerId": 12212,12
"type": "LOAN",13
"balance": 98914
}15
]16
""";17
TEXT BLOCKS
@techgirl1908

Text cannot begin on
same line as """
System.out.println(""" Hey y'all! """);
1
2
3
4
5
System.out.println("""6
Hey y'all!""");7
8
9
Hey y'all!11
""");12
System.out.println("""
Hey y'all!""");
1
2
System.out.println(""" Hey y'all! """);3
4
5
6
7
8
9
Hey y'all!11
""");12
System.out.println("""
Hey y'all!
""");
1
2
System.out.println(""" Hey y'all! """);3
4
5
Hey y'all!""");7
8
9
10
11
12

@Test1
3
6
9
11
13
.stream()14
18
}20
@techgirl1908

public static List<String> getAccountIds_mocked(){
return Arrays.asList("13344", "13455", "13566", "14010");
}
1
2
3
return Arrays.asList("13344", "13455", "13566", "14010");
public static List<String> getAccountIds_mocked(){1
2
}3
public static List<String> getAccountIds_mocked(){
return List.of("13344", "13455", "13566", "14010");
}
COLLECTION CONVENIENCE METHOD
@techgirl1908

Map users = new HashMap();
users.put("john", 123);
users.put("alice", 456);
users.put("sue", 789);
1
2
3
4
Map users = Map.of("john", 123, "alice", 456, "sue", 789);1
@techgirl1908

The of() method
creates immutable
collections
@techgirl1908

Map users = Map.of(
"john", 123,
"alice", 456,
"sue", 789);
1
2
3
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users.put("bob", 000);
users.remove("alice");
@techgirl1908

No Hate on Java 8, But 9–14 Reign Supreme

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