How to use Lambda expressions in java for nested if-else and for loop together - selenium

Question

I have following Code where i will receive list of names as parameter.In the loop, first i'm assigning index 0 value from list to local variable name. There after comparing next values from list with name. If we receive any non-equal value from list, i'm assigning value of result as 1 and failing the test case.
Below is the Array list
List<String> names= new ArrayList<String>();
names.add("John");
names.add("Mark");
Below is my selenium test method
public void test(List<String> names)
String name=null;
int a=0;
for(String value:names){
if(name==null){
System.out.println("Value is null");
name=value;
}
else if(name.equals(value)){
System.out.println("Received Same name");
name=value;
}
else{
a=1;
Assert.fail("Received different name in between");
}
}
How can i convert above code into lambda expressions?. I'm using cucumber data model, hence i receive data as list from feature file. Since i can't give clear explanation, just posted the example logic i need to convert to lambda expression.

Answer 1

Here's the solution: it cycles all element in your list checking if are all the same.
You can try adding or editing the list so you can have different outputs. I've written the logic, you can easly put it into a JUnit test
List<String> names= new ArrayList<>();
names.add("John");
names.add("Mark");
String firstEntry = names.get(0);
boolean allMatch = names.stream().allMatch(name -> firstEntry.equals(name));
System.out.println("All names are the same: "+allMatch);

Answer 2

Are you looking for duplicates, whenever you have distinct value , set a=1 and say assert to fail. You can achieve this by :
List<String> names= new ArrayList<String>();
names.add("John");
names.add("Mark");
if (names.stream().distinct().limit(2).count() > 1) {
a= 1,
Assert.fail("Received different name in between");
} else {
System.out.println("Received Same name");
}