Example 1: Define lambda expressions as method parameters
import java.util.ArrayList;
class Main {
public static void main(String[] args) {
// create an ArrayList
ArrayList<String> languages = new ArrayList<>();
// add elements to the ArrayList
languages.add("java");
languages.add("swift");
languages.add("python");
System.out.println("ArrayList: " + languages);
// pass lambda expression as parameter to replaceAll() method
languages.replaceAll(e -> e.toUpperCase());
System.out.println("Updated ArrayList: " + languages);
}
}
Output
ArrayList: [java, swift, python] Updated ArrayList: [JAVA, SWIFT, PYTHON]
In the above example, we have created an arraylist named languages. Notice the line,
languages.replaceAll(e -> e.toUpperCase());
Here, e -> e.toUpperCase()
is a lambda expression. It takes all elements of the arraylist and converts them into uppercase.
Example 2: Pass multiline lambda body as function arguments
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 foEach() method
// pass lambda as argument fo forEach()
// reverse each element of ArrayList
System.out.print("Reversed ArrayList: ");
languages.forEach((e) -> {
// body of lambda expression
String result = "";
for (int i = e.length()-1; i >= 0 ; i--)
result += e.charAt(i);
System.out.print(result + ", ");
});
}
}
Output
ArrayList: [java, python] Reversed ArrayList: avaj, nohtyp,
In the above example, we have created an arraylist languages. Notice the line,
languages.forEach((e) -> {
// body of lambda expression
String result = "";
for (int i = e.length()-1; i >= 0 ; i--)
result += e.charAt(i);
System.out.print(result + ", ");
});
Here, we are passing lambda expression as an argument to the ArrayList forEach() method. The lambda expression will reverse each element of the arraylist.
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