Core Java basics
Practice variables, loops, methods, classes, objects, inheritance, and exceptions.
Core Java Practice
Java 8 Online Compiler
Run Java 8 code online with CodingCool. Practice core Java, OOP, arrays, strings, collections, lambdas, streams, and interview examples without installing a local IDE.
Open Java 8 CompilerGood use cases for Java 8
Collections and streams
Try List, Map, Set, sorting, filtering, mapping, and common stream operations.
Interview questions
Run small programs for strings, arrays, recursion, frequency maps, and pattern printing.
Java 8 stream example
import java.util.Arrays;
public class Main {
public static void main(String[] args) {
int sum = Arrays.stream(new int[] {1, 2, 3, 4})
.filter(n -> n % 2 == 0)
.sum();
System.out.println(sum);
}
}