- Online Java Compiler
- What is Java?
- Why learn Java?
- Features of this tool
- Learn Other Programming Language?
- Download Result
- Close File
- Save
- Share the Code
- Share the Code
- About online-java.com
- Keyboard Shortcuts
- Report a bug
- Data policy
- online compiler and debugger for c/c++
- Running Turbo C Project
- Save Project
- Extra Compiler Flags
- Are you sure you want to delete file ` `?
- New File
- Rename File
- Share Link
- Lost connection to server
- Debug session stopped
- Debug mode for python program is not yet supported.
- Login to your account
- Login with
- Run Console session stopped
- Add School/University/Institute
- Keyboard Shortcuts
- Online Java — IDE, Code Editor, Compiler
- What is Java?
- Why learn Java?
- Features of this tool
- Learn Other Programming Language?
- Java online compiler
- Taking inputs (stdin)
- Adding dependencies
- About Java
- Syntax help
- Variables
- Loops
- 1. If Else:
- 2. Switch:
- 3. For:
- 4. While:
- 5. Do-While:
- Classes and Objects
- How to create a Class:
- Example:
- How to create a Object:
- How to define methods in a class:
- Collections
- Advantages:
Online Java Compiler
Online Java is a web-based tool powered by ACE code editor. Build, Run & Share Java code online using online-java’s IDE for free. It’s one of the quick, robust, powerful online compilers for java language. Don\’t worry about setting up java environment in your local. Now Run the java code in your favorite browser instantly. Getting started with this editor is so easy and fast. Just write the program and click the RUN button!! Code can be saved online by using the SHARE option that enables you to access your code anywhere using internet.
What is Java?
Java is a popular general-purpose programming language which was originally developed by James Gosling at Sun Microsystems (later acquired by Oracle). Java is fast, secure, and reliable. It is widely used for developing desktop and mobile applications, embedded systems, game consoles, supercomputers, big data processing, and so on. According to Oracle, Java runs on 3 billion devices worldwide, which makes it one of the most popular programming languages.
Why learn Java?
- Web-based Applications
- Mobile App Development
- Desktop GUI Applications
- Gaming Applications
- Big Data Technologies
- Distributed Applications
- Cloud-Based Applications
- IoT Applications
Features of this tool
- Simple & Clean Design, Lightweight, Easy & Fast
- Interactive program execution which makes the user to give program inputs at real time
- Helpful for beginners to learn and practice programs
- Dark & Light theme options and customizable code editor with more themes
- Options to Copy or Download the Output of the Program
- Expandable Output Terminal
- Coding sharing option helps you to save your code in cloud so that it can be accessed anytime and anywhere with internet
Learn Other Programming Language?
Visit online-ide.com to learn and practice top programming languages — C, C++, Java, Python, Ruby, PHP, R, GoLang
Download Result
Close File
Your changes will be lost. Are you sure you want to Close the file ?
Save
Do you want to save the file ?
Share the Code
Share the Code
About online-java.com
Online Java is a web-based tool powered by ACE code editor. Build, Run & Share Java code online using online-java’s IDE for free. It’s one of the quick, robust, powerful online compilers for java language. Don\’t worry about setting up java environment in your local. Now Run the java code in your favorite browser instantly. Getting started with this editor is so easy and fast. Just write the program and click the RUN button!! Code can be saved online by using the SHARE option that enables you to access your code anywhere using internet.
Keyboard Shortcuts
- Run Code — F8
- Share Code — F9
- Save Code — F10
- Open Editor Command Palette — F1
Report a bug
If you encounter a bug or have questions or suggestions for improvements, please report it via feedback.
Data policy
No data is saved in the server. The code is sent to the server for execution and will be cleared after completion. Shared Code will be saved in the server till the selected expiry period.
Copyright © 2021 online-ide.com
online compiler and debugger for c/c++
New Version of OnlineGDB is available. Please save your data and refresh page to update.
Running Turbo C Project
Save Project
Extra Compiler Flags
Are you sure you want to delete file ` `?
New File
Rename File
Share Link
Lost connection to server
Oops! Connection to server is lost. Please refresh the page to reconnect.
Debug session stopped
Debug session is being stopped due to inactivity.
Debug mode for python program is not yet supported.
Login to your account
Login with
Run Console session stopped
Run Console is being stopped due to inactivity.
Add School/University/Institute
Keyboard Shortcuts
IDE Shortcuts: New file : Ctrl-M Run Code : F9 Debug Code : F8 Save Project : Ctrl-S Beautify Code : Ctrl-B Settings Menu : Ctrl-Shift-S Info : Ctrl-I Editor Shortcuts: showSettingsMenu : Ctrl-, goToNextError : Alt-E goToPreviousError : Alt-Shift-E selectall : Ctrl-A gotoline : Ctrl-L fold : Alt-L|Ctrl-F1 unfold : Alt-Shift-L|Ctrl-Shift-F1 toggleFoldWidget : F2 toggleParentFoldWidget : Alt-F2 foldOther : Alt-0 unfoldall : Alt-Shift-0 findnext : Ctrl-K findprevious : Ctrl-Shift-K selectOrFindNext : Alt-K selectOrFindPrevious : Alt-Shift-K find : Ctrl-F overwrite : Insert selecttostart : Ctrl-Shift-Home gotostart : Ctrl-Home selectup : Shift-Up golineup : Up selecttoend : Ctrl-Shift-End gotoend : Ctrl-End selectdown : Shift-Down golinedown : Down selectwordleft : Ctrl-Shift-Left gotowordleft : Ctrl-Left selecttolinestart : Alt-Shift-Left gotolinestart : Alt-Left|Home selectleft : Shift-Left gotoleft : Left selectwordright : Ctrl-Shift-Right gotowordright : Ctrl-Right selecttolineend : Alt-Shift-Right gotolineend : Alt-Right|End selectright : Shift-Right gotoright : Right selectpagedown : Shift-Pagedown gotopagedown : Pagedown selectpageup : Shift-Pageup gotopageup : Pageup scrollup : Ctrl-Up scrolldown : Ctrl-Down selectlinestart : Shift-Home selectlineend : Shift-End togglerecording : Ctrl-Alt-E replaymacro : Ctrl-Shift-E jumptomatching : Ctrl-P selecttomatching : Ctrl-Shift-P expandToMatching : Ctrl-Shift-M removeline : Ctrl-D duplicateSelection : Ctrl-Shift-D sortlines : Ctrl-Alt-S togglecomment : Ctrl-/ toggleBlockComment : Ctrl-Shift-/ modifyNumberUp : Ctrl-Shift-Up modifyNumberDown : Ctrl-Shift-Down replace : Ctrl-H undo : Ctrl-Z redo : Ctrl-Shift-Z|Ctrl-Y copylinesup : Alt-Shift-Up movelinesup : Alt-Up copylinesdown : Alt-Shift-Down movelinesdown : Alt-Down del : Delete backspace : Shift-Backspace|Backspace cut_or_delete : Shift-Delete removetolinestart : Alt-Backspace removetolineend : Alt-Delete removewordleft : Ctrl-Backspace removewordright : Ctrl-Delete outdent : Shift-Tab indent : Tab blockoutdent : Ctrl-[ blockindent : Ctrl-] transposeletters : Ctrl-T touppercase : Ctrl-U tolowercase : Ctrl-Shift-U expandtoline : Ctrl-Shift-L addCursorAbove : Ctrl-Alt-Up addCursorBelow : Ctrl-Alt-Down addCursorAboveSkipCurrent : Ctrl-Alt-Shift-Up addCursorBelowSkipCurrent : Ctrl-Alt-Shift-Down selectMoreBefore : Ctrl-Alt-Left selectMoreAfter : Ctrl-Alt-Right selectNextBefore : Ctrl-Alt-Shift-Left selectNextAfter : Ctrl-Alt-Shift-Right splitIntoLines : Ctrl-Alt-L alignCursors : Ctrl-Alt-A findAll : Ctrl-Alt-K showKeyboardShortcuts : Ctrl-Alt-H
Online Java — IDE, Code Editor, Compiler
Online Java is a web-based tool powered by ACE code editor. Build, Run & Share Java code online using online-java’s IDE for free. It’s one of the quick, robust, powerful online compilers for java language. Don’t worry about setting up java environment in your local. Now Run the java code in your favorite browser instantly. Getting started with this editor is so easy and fast. Just write the program and click the RUN button!! Code can be saved online by using the SHARE option that enables you to access your code anywhere using internet.
What is Java?
Java is a popular general-purpose programming language which was originally developed by James Gosling at Sun Microsystems (later acquired by Oracle). Java is fast, secure, and reliable. It is widely used for developing desktop and mobile applications, embedded systems, game consoles, supercomputers, big data processing, and so on. According to Oracle, Java runs on 3 billion devices worldwide, which makes it one of the most popular programming languages.
Why learn Java?
- Web-based Applications
- Mobile App Development
- Desktop GUI Applications
- Gaming Applications
- Big Data Technologies
- Distributed Applications
- Cloud-Based Applications
- IoT Applications
Features of this tool
- Simple & Clean Design, Lightweight, Easy & Fast
- Interactive program execution which makes the user to give program inputs at real time
- Helpful for beginners to learn and practice programs
- Dark & Light theme options and customizable code editor with more themes
- Options to Copy or Download the Output of the Program
- Expandable Output Terminal
- Coding sharing option helps you to save your code in cloud so that it can be accessed anytime and anywhere with internet
Learn Other Programming Language?
Visit online-ide.com to learn and practice top programming languages — C, C++, Java, Python, Ruby, PHP, R, GoLang
Java online compiler
Write, Run & Share Java code online using OneCompiler’s Java online compiler for free. It’s one of the robust, feature-rich online compilers for Java language, running the Java LTS version 17. Getting started with the OneCompiler’s Java editor is easy and fast. The editor shows sample boilerplate code when you choose language as Java and start coding.
Taking inputs (stdin)
OneCompiler’s Java online editor supports stdin and users can give inputs to the programs using the STDIN textbox under the I/O tab. Using Scanner class in Java program, you can read the inputs. Following is a sample program that shows reading STDIN ( A string in this case ).
import java.util.Scanner; class Input < public static void main(String[] args) < Scanner input = new Scanner(System.in); System.out.println("Enter your name: "); String inp = input.next(); System.out.println("Hello, " + inp); >>
Adding dependencies
OneCompiler supports Gradle for dependency management. Users can add dependencies in the build.gradle file and use them in their programs. When you add the dependencies for the first time, the first run might be a little slow as we download the dependencies, but the subsequent runs will be faster. Following sample Gradle configuration shows how to add dependencies
apply plugin:'application' mainClassName = 'HelloWorld' run < standardInput = System.in >sourceSets < main < java < srcDir './' >> > repositories < jcenter() >dependencies < // add dependencies here as below implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.9' >
About Java
Java is a very popular general-purpose programming language, it is class-based and object-oriented. Java was developed by James Gosling at Sun Microsystems ( later acquired by Oracle) the initial release of Java was in 1995. Java 17 is the latest long-term supported version (LTS). As of today, Java is the world’s number one server programming language with a 12 million developer community, 5 million students studying worldwide and it’s #1 choice for the cloud development.
Syntax help
Variables
short x = 999; // -32768 to 32767 int x = 99999; // -2147483648 to 2147483647 long x = 99999999999L; // -9223372036854775808 to 9223372036854775807 float x = 1.2; double x = 99.99d; byte x = 99; // -128 to 127 char x = 'A'; boolean x = true;
Loops
1. If Else:
When ever you want to perform a set of operations based on a condition If-Else is used.
if(conditional-expression) < // code >else < // code >
2. Switch:
Switch is an alternative to If-Else-If ladder and to select one among many blocks of code.
3. For:
For loop is used to iterate a set of statements based on a condition. Usually for loop is preferred when number of iterations is known in advance.
for(Initialization; Condition; Increment/decrement) < //code >
4. While:
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
5. Do-While:
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
Classes and Objects
Class is the blueprint of an object, which is also referred as user-defined data type with variables and functions. Object is a basic unit in OOP, and is an instance of the class.
How to create a Class:
class keyword is required to create a class.
Example:
How to create a Object:
How to define methods in a class:
public class Greeting < static void hello() < System.out.println("Hello.. Happy learning!"); >public static void main(String[] args) < hello(); >>
Collections
Collection is a group of objects which can be represented as a single unit. Collections are introduced to bring a unified common interface to all the objects.
Collection Framework was introduced since JDK 1.2 which is used to represent and manage Collections and it contains:
This framework also defines map interfaces and several classes in addition to Collections.
Advantages:
- High performance
- Reduces developer’s effort
- Unified architecture which has common methods for all objects.