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In this example, we will learn to pass lambda expressions as method parameters in Java.
To understand this example, you should know the followingJava ProgrammingTopic:
import java.util.ArrayList;
class Main {
public static void main(String[] args) {
//Create an ArrayList
ArrayList<String> languages = new ArrayList<>();
//Add elements to ArrayList
languages.add("java");
languages.add("swift");
languages.add("python");
System.out.println("ArrayList: "); + languages);
//Pass lambda expression as a parameter to the replaceAll() method
languages.replaceAll(e -> e.toUpperCase());
System.out.println("Updated ArrayList: "); + languages);
}
}Output Result
ArrayList: [java, swift, python] Updated ArrayList: [JAVA, SWIFT, PYTHON]
In the above example, we created an arraylist named languages. Note this line,
languages.replaceAll(e -> e.toUpperCase());
Here, e -> e.toUpperCase() is a lambda expression. It accepts all elements of the arraylist and converts them to uppercase.
import java.util.ArrayList;
import java.util.Arrays;
class Main {
public static void main(String[] args) {
//Create an ArrayList
ArrayList<String> languages = new ArrayList<>(Arrays.asList("java", "python"));
System.out.println("ArrayList: "); + languages);
//Call the forEach() method
//Pass lambda as a parameter to forEach()
//Reverse each element of ArrayList
System.out.print("Reversed ArrayList: ");
languages.forEach((e) -> {
//Lambda Expression Body
String result = "";
for (int i = e.length() -1; i >= 0 ; i--)
result += e.charAt(i);
System.out.print(result + ", ");
});
}
}Output Result
ArrayList: [java, python] Reversed ArrayList: avaj, nohtyp,
In the above example, we create an arraylist named languages. Note this line,
languages.forEach((e) -> {
//Lambda Expression Body
String result = "";
for (int i = e.length() -1; i >= 0 ; i--)
result += e.charAt(i);
System.out.print(result + ", ");
});In this example, we pass the lambda expression as a parameter toArrayList forEach()Method. The lambda expression reverses each element of the arraylist.