Learn IJAVA with Real Code Examples

System.out.println("Hello World");

A simple IJava cell printing 'Hello World'.

int[] numbers = {1, 2, 3, 4, 5};
for (int n : numbers) {
    System.out.println(n);
}

An IJava cell demonstrating iteration over an array.

for (int i = 1; i <= 5; i++) {
    System.out.println(i);
}

A basic for-loop printing numbers from 1 to 5.

String name = "Saurav";
System.out.println("Hello, " + name);

Declaring and using variables in IJava.

import java.util.*;
List<String> items = Arrays.asList("A", "B", "C");
items.forEach(System.out::println);

Creating and printing an ArrayList inside IJava.

import java.util.*;
Map<String, Integer> map = new HashMap<>();
map.put("One", 1);
map.put("Two", 2);
map.forEach((k, v) -> System.out.println(k + " = " + v));

Using a HashMap inside an IJava cell.

int add(int a, int b) {
    return a + b;
}
System.out.println(add(3, 4));

Defining and calling a custom method.

class Person {
    String name
    int age
    Person(String n, int a) {
        name = n;
        age = a;
    }
}
Person p = new Person("Alex", 21);
System.out.println(p.name + " - " + p.age);

Defining a small class and creating an instance.

import java.util.*;
Arrays.asList(1, 2, 3, 4, 5)
    .stream()
    .map(n -> n * n)
    .forEach(System.out::println);

Using Java Streams inside a Jupyter cell.

try {
    int x = 10 / 0;
} catch (Exception e) {
    System.out.println("Error: " + e.getMessage());
}

Simple exception handling in an IJava notebook.