Learn Ijava - 10 Code Examples & CST Typing Practice Test

IJava is a Jupyter kernel that allows you to run Java code inside Jupyter Notebooks. It brings interactive Java programming to the notebook environment, enabling code execution, documentation, and visualization together.

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Hello World in IJava Array Iteration in IJava Simple For Loop in IJava IJava Variable Assignment IJava List Example IJava Map Example IJava Function Definition IJava Class Example IJava Stream API Example IJava Try/Catch Example

Learn IJAVA with Real Code Examples

Updated Nov 26, 2025

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Code Sample Descriptions

Hello World in IJava

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

A simple IJava cell printing 'Hello World'.

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Array Iteration in IJava

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

An IJava cell demonstrating iteration over an array.

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Simple For Loop in IJava

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

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

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IJava Variable Assignment

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

Declaring and using variables in IJava.

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IJava List Example

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

Creating and printing an ArrayList inside IJava.

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IJava Map Example

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.

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IJava Function Definition

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

Defining and calling a custom method.

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IJava Class Example

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.

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IJava Stream API Example

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.

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IJava Try/Catch Example

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

Simple exception handling in an IJava notebook.

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Frequently Asked Questions about Ijava

What is Ijava?

What are the primary use cases for Ijava?

Teaching Java programming interactively. Exploring Java algorithms and data structures. Documenting Java experiments and examples. Creating tutorials with combined text and code. Prototyping Java logic and visualization

What are the strengths of Ijava?

Interactive Java development in a notebook. Combines coding, visualization, and documentation. Useful for teaching and tutorials. Supports popular Java libraries. Easy to share experiments via notebook export

What are the limitations of Ijava?

Not suitable for production Java applications. Performance limited by notebook environment. Library management may require manual setup. Kernel stability can vary for large computations. Limited GUI or complex application support

How can I practice Ijava typing speed?

CodeSpeedTest offers 10+ real Ijava code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Hello World in IJava

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

A simple IJava cell printing 'Hello World'.

Let’s Try →

Array Iteration in IJava

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

An IJava cell demonstrating iteration over an array.

Let’s Try →

Simple For Loop in IJava

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

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

Let’s Try →

IJava Variable Assignment

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

Declaring and using variables in IJava.

Let’s Try →

IJava List Example

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

Creating and printing an ArrayList inside IJava.

Let’s Try →

IJava Map Example

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.

Let’s Try →

IJava Function Definition

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

Defining and calling a custom method.

Let’s Try →

IJava Class Example

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.

Let’s Try →

IJava Stream API Example

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.

Let’s Try →

IJava Try/Catch Example

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

Simple exception handling in an IJava notebook.

Let’s Try →

Frequently Asked Questions about Ijava

What is Ijava?

What are the primary use cases for Ijava?

What are the strengths of Ijava?

What are the limitations of Ijava?

How can I practice Ijava typing speed?

CodeSpeedTest offers 10+ real Ijava code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.