In this tutorial, you will learn how to create, run, and package a simple Java application that prints
Hello, World! to the system output. Along the way, you will get familiar with IntelliJ IDEA features for boosting your productivity as a developer: coding assistance and supplementary tools.
Watch the screencast and follow the step-by-step instructions below:
Prepare a project
A JRE is a Java Runtime Environment and is the files needed to support running a java application on a machine. It differs from a JDK (Java Development Kit) in that it is intended to be delivered with java applications and does not include developer documentation and the like. I would not worry about having more than one JRE/JDK.
Create a new Java project
In IntelliJ IDEA, a project helps you organize your source code, tests, libraries that you use, build instructions, and your personal settings in a single unit.
Create a package and a class
Packages are used for grouping together classes that belong to the same category or provide similar functionality, for structuring and organizing large applications with hundreds of classes.
Together with the file, IntelliJ IDEA has automatically generated some contents for your class. In this case, the IDE has inserted the package statement and the class declaration.
This is done by means of file templates. Depending on the type of the file that you create, the IDE inserts initial code and formatting that is expected to be in all files of that type. For more information on how to use and configure templates, refer to File templates.
The Project tool window Alt+1 displays the structure of your application and helps you browse the project.
In Java, there's a naming convention that you should follow when you name packages and classes.
Write the codeAdd the main() method using live templatesHow To Run Java Apps On Mac Computer
Live templates are code snippets that you can insert into your code.
main is one of such snippets. Usually, live templates contain blocks of code that you use most often. Using them can save you some time as you don't have to type the same code over and over again.
For more information on where to find predefined live templates and how to create your own, refer to Live templates.
How To Run A Java Program
You can also add the statement using the
sout live template.
Call the println() method using code completion
After the
main() method declaration, IntelliJ IDEA automatically places the caret at the next line. Let's call a method that prints some text to the standard system output.
Basic code completion analyses the context around the current caret position and and provides suggestions as you type. You can open the completion list manually by pressing Ctrl+Space.
For information on different completion modes, refer to Code completion.
Build and run the application
Valid Java classes can be compiled into bytecode. You can compile and run classes with the
main() method right from the editor using the green arrow icon in the gutter.
When you click Run, IntelliJ IDEA creates a special run configuration that performs a series of actions. First, it builds your application. On this stage, compiles your source code into JVM bytecode.
Once javac finishes compilation, it places the compiled bytecode to the out directory, which is highlighted with yellow in the Project tool window.
After that, the runs the bytecode.
Record mac screen app. Automatically created run configurations are temporary, but you can modify and save them.
If you want to reopen the Run tool window, press Alt+4.
IntelliJ IDEA automatically analyzes the file that is currently opened in the editor and searches for different types of problems: from syntax errors to typos. The Inspections widget at the top-right corner of the editor allows you to quickly see all the detected problems and look at each problem in detail. For more information, refer to Instant analysis of the current file.
Package the application in a JAR
When the code is ready, you can package your application in a Java archive (JAR) so that you can share it with other developers. A built Java archive is called an artifact.
Create an artifact configuration for the JAR
Build the JAR artifact![]()
Run the packaged application
To make sure that the JAR artifact is created correctly, you can run it.
Use Find ActionCtrl+Shift+A to search for actions and settings across the entire IDE.
Create a run configuration for the packaged application
To run a Java application packaged in a JAR, IntelliJ IDEA allows you to create a dedicated run configuration.
Run configurations allow you to define how you want to run your application, with which arguments and options. You can have multiple run configurations for the same application, each with its own settings.
Execute the run configuration
The process has exited successfully, which means that the application is packaged correctly.
Last modified: 19 August 2020
Hello, World in Java on Mac OS XThis documents instructs you on how to setup a Java programmingenvironment for your Mac OS X computer and provides a step-by-stepguide to creating, compiling, and executing a Java program.We assume you are running at least OS X 10.2.3.All of the software is freely available on the Web.
You will use the Java compiler javac to compile your Java programs andthe Java interpreter java to run them.Mac OS X includes implementation of Java 2 Standard Edition (J2SE) 1.4.1,so there is nothing to do in this step.
You will type commands in an application called the Terminal.You might enjoy reading Neal Stephenson's light-heartedessay In the Beginningwas the Command Line.
Run Java Apps On Android
You will type and edit your programs in a text editor called JEdit.JEdit is similar to conventional word processors like MS Word,but it features many specialized programming tools includingsyntax highlighting, bracket matching, auto indenting, indentshifting, line numbering, and commenting out code. It's even written in Java.
Now you are ready to write your first Java program.
It is now time to convert your Java program into a form more amenable for executingon a computer.
Now it is time to run your program. This is the fun part.
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Where Is Java On Mac
When I try to run java I get: Exception in thread 'main'java.lang.NoClassDefFoundErrorYour CLASSPATH may have been set by some other program so that it no longer includes the current working directory in the search path. Try running your program with the command line
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