Welcome to XCODX Online Compiler
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Every AP Computer Science A exam and countless university CS1/CS2 sequences are taught in Java, and the language is just as entrenched in industry — Amazon, Netflix's backend, and nearly every major bank run critical systems on the JVM. Modern Java is far more expressive than its old reputation suggests: records, pattern matching for switch, text blocks, and virtual threads have all landed in recent LTS releases. This online Java compiler pairs a modern JDK with a real interactive terminal, meaning Scanner and System.in behave exactly as they do in IntelliJ or a local shell — your program prints its prompt, then sits and waits for you to type.
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number: ");
int n = sc.nextInt();
long fact = 1;
for (int i = 2; i <= n; i++) {
fact *= i;
}
System.out.printf("%d! = %d%n", n, fact);
sc.close();
}
}Run AP Computer Science A practice problems and university OOP assignments without wrestling with JDK installs or IDE licensing, solve LeetCode and HackerRank problems in the language most big-tech interview loops still accept by default, or confirm exactly what a String method, ArrayList operation, or integer overflow does before an exam. Because Scanner works against a live terminal, textbook exercises that read input interactively run unmodified — the same code your professor demonstrates in class works here verbatim.
Fully. The sandbox attaches your program to a real terminal, so sc.nextInt(), sc.nextLine(), and hasNext() loops block for live keyboard input exactly like a local console application. You don't pre-load input into a text box — the program prompts, you answer, it continues.
A modern LTS-line JDK, so contemporary language features — var, records, enhanced switch expressions, text blocks, and the streams API — compile and run. If you're studying from an older textbook, all legacy syntax remains valid too; Java's backward compatibility is famously strict.
No — there's no dependency resolution in the sandbox, so external libraries like Gson, JUnit, or Apache Commons aren't available. Everything in the JDK itself is: collections, java.time, regex, concurrency utilities, and I/O. Your code should live in a single file with one public class.
Main.javatext/x-javanew Scanner(System.in)public class Main {
public static void main(String[] args) {
System.out.println("Hello from Java!");
System.out.println("Welcome to XCODX Online Compiler!");
}
}JVM notices such as "Picked up JAVA_TOOL_OPTIONS" and unchecked-operation notes are filtered from the output pane.