Run java files in terminal

How to run a Java Class in Terminal

I have done a lot of research and, I could not find how to solve my problem. I saw that there are a lot of people who ask this question, but still none of them answered it for me. I am a beginner at java and I made a simple calculator in Eclipse.

import java.util.Scanner; public class Calculator < public static void main(String[] args) < Scanner numInput = new Scanner(System.in); double fnum, snum; String operation; System.out.println("First number: "); fnum = numInput.nextDouble(); System.out.println("Second number: "); snum = numInput.nextDouble(); Scanner oper = new Scanner(System.in); System.out.println("Please select one of the following operations: "); System.out.println("+"); System.out.println("-"); System.out.println("/"); System.out.println("*"); operation = oper.next(); switch (operation)< case "+": System.out.println("Your answer is: " + (fnum + snum)); break; case "-": System.out.println("Your answer is: " + (fnum - snum)); break; case "*": System.out.println("Your answer is: " + (fnum * snum)); break; case "/": System.out.println("Your answer is: " + (fnum / snum)); break; >> > 

Later I went into the Workspace folder to find the Calculator.class file. I opened terminal and typed:

Danylo-RIB:~ mac$ java /Users/mac/Documents/workspace/Calculator/bin/Calculator.class 

I followed all the instructions on how to run a class in MacOs Terminal, but all I got for an answer in my terminal instead of my program was:

Danylo-RIB:~ mac$ java /Users/mac/Documents/workspace/Calculator/bin/Calculator.class Error: Could not find or load main class .Users.mac.Documents.workspace.Calculator.bin.Calculator.class Danylo-RIB:~ mac$ 

So my question is, how do I do this? How do I run a class in Terminal? EDIT: Okay, thanks to the people who answered my question!

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How to Run a Java File in Terminal: A Step-by-Step Guide

Learn how to run a Java file in terminal with this comprehensive guide. Follow step-by-step instructions and troubleshooting tips to compile and run Java programs using the command line.

• Install JDK on your computer
• Navigate to the directory where the Java file is saved
• How to Run a Java File from Terminal or Command Prompt with
• Compile the Java file using the “javac” command
• Run the Java file using the “java” command
• Best practices for Java programming
• Other helpful code examples for running a Java file in the terminal
• Conclusion
• Can you run Java in terminal?
• How to run Java file in terminal Linux?
• How to run Java file in terminal Mac?
• How to run Java program in terminal Windows?

Java is one of the most popular programming languages in the world, and it is widely used for developing desktop, web, and mobile applications. Running a Java file in the terminal is an essential skill for any Java developer, especially if you are working on a project that requires command-line interaction. In this article, we will discuss how to run a Java file in terminal, step-by-step.

Install JDK on your computer

Before we can start running Java files in the terminal, we need to install the Java Development Kit (JDK) on our computer. The JDK is a software development environment that includes the Java Runtime Environment (JRE), the Java compiler, and other development tools.

Explanation of what JDK is and why it is needed

The JDK is required for developing Java applications because it provides all the tools and libraries needed for writing, compiling, and executing Java code. The JRE, which is included in the JDK, is the environment in which Java applications run.

Step-by-step guide to install JDK on Windows, Mac, and Linux

The installation process for the JDK varies depending on your operating system. Here is a step-by-step guide to installing the JDK on Windows, Mac, and Linux.

Windows

1. Download the JDK from the Oracle website.
2. Double-click the downloaded file to start the installation process.
3. Follow the on-screen instructions to complete the installation.

Mac

1. Download the JDK from the Oracle website.
2. Double-click the downloaded file to mount the disk image.
3. Double-click the JDK package to start the installation process.
4. Follow the on-screen instructions to complete the installation.

Linux

1. Open a terminal window.
2. Type the following command to install the JDK: sudo apt-get install default-jdk
3. Enter your password when prompted.
4. Follow the on-screen instructions to complete the installation.

Troubleshooting common issues during installation

If you encounter any issues during the installation process, the first thing to check is whether you have downloaded the correct version of the JDK for your operating system. You should also ensure that you have administrative privileges on your computer, as the installation process may require elevated permissions.

Navigate to the directory where the Java file is saved

Once you have installed the JDK, you can start running Java files in the terminal. The first step is to navigate to the directory where the Java file is saved.

Explanation of what a directory is and how to navigate to it

A directory, also known as a folder, is a container for files and other directories. To navigate to a directory in the terminal, you need to use the cd command, which stands for “change directory”. Here are some commonly used cd commands:

• cd : Navigate to your home directory.
• cd .. : Navigate to the parent directory.
• cd /path/to/directory : Navigate to a specific directory.

How to locate the Java file directory using the command prompt or terminal

To locate the directory where the Java file is saved, you can use the ls command on Mac and Linux or the dir command on Windows. These commands will list all the files and directories in the current directory.

Once you have located the directory where the Java file is saved, you can use the cd command to navigate to it.

Tips for organizing and managing Java files

It is good practice to organize your Java files into directories based on their functionality or purpose. This will make it easier to manage and maintain your code as your project grows.

How to Run a Java File from Terminal or Command Prompt with

Hello friends! My name is Ajay, and I am a rising senior in high school! In this video, I am going to Duration: 8:55

Compile the Java file using the “javac” command

The next step is to compile the Java file using the javac command. The javac command is used to compile Java source code into bytecode, which can be executed by the Java Virtual Machine (JVM).

Explanation of what the “javac” command does and how it works

The javac command takes a Java source file as input and generates a class file as output. The class file contains the bytecode that can be executed by the JVM.

Step-by-step guide to compile a Java file using the “javac” command

Here is a step-by-step guide to compiling a Java file using the javac command:

1. Open a terminal window.
2. Navigate to the directory where the Java file is saved using the cd command.
3. Type the following command to compile the Java file: javac filename.java
4. If the compilation is successful, a class file with the same name as the Java file will be generated in the same directory.

Common errors that occur during compilation and how to fix them

Some common errors that occur during compilation include syntax errors, missing dependencies, and incorrect class names. To fix these errors, you should carefully review the error message and make the necessary changes to the source code.

Run the Java file using the “java” command

Once you have compiled the Java file, you can run it using the java command.

Explanation of what the “java” command does and how it works

The java command is used to execute Java bytecode on the JVM. It takes a class file as input and runs the main method defined in the class.

Step-by-step guide to run a compiled Java file using the “java” command

Here is a step-by-step guide to running a compiled Java file using the java command:

1. Open a terminal window.
2. Navigate to the directory where the class file is saved using the cd command.
3. Type the following command to run the Java file: java classname
4. If the Java program is successful, the output will be displayed in the terminal.

Common errors that occur during running a Java program and how to fix them

Some common errors that occur during running a Java program include missing dependencies, incorrect command-line arguments, and runtime exceptions. To fix these errors, you should carefully review the error message and make the necessary changes to the source code.

Best practices for Java programming

To become a proficient java developer, it is important to follow best practices for writing code. Here are some best practices for java programming:

Explanation of best practices for writing Java programs

• Use meaningful variable names that describe the purpose of the variable.
• Comment your code to explain its purpose and how it works.
• Follow coding conventions, such as using camelCase for variable names and PascalCase for class names.
• Write efficient, readable, and maintainable code.

Tips for writing efficient, readable, and maintainable code

• Break your code into modular functions or methods.
• Use object-oriented programming principles to encapsulate functionality.
• Avoid using magic numbers or hard-coded values.
• Use exception handling to gracefully handle errors.

Examples of best practices

Here are some examples of best practices for Java programming:

• Use final keyword to declare constants.
• Use try-with-resources statement to manage resources.
• Use StringBuilder instead of String for string concatenation.

Other helpful code examples for running a Java file in the terminal

In java, cmd java compile code example

javac MyFisrtProgam.java // enter to compile java MyfirstProgram // run program 

// Assuming that you have an executable jar java -jar myJavaProject.jar// Assuming that you have packaged jar java -jar target/myJavaProject.jar

In java, run java from terminal code example

//Run this line to compile javac programName.java//Run this line to run java programName

In java, how to run a java file in terminal code example

javac FirstJavaProgram.java

In java, run java application in commande line code example

java -jar target/spring-cloud-gateway-keycloak-oauth2-0.0.1-SNAPSHOT.jarjava -jar target/product-service-0.0.1-SNAPSHOT.jar

Conclusion

In conclusion, running a Java file in the terminal is an essential skill for any Java developer. In this article, we have discussed how to install the JDK, navigate to the directory where the Java file is saved, compile the Java file using the javac command, run the Java file using the java command, and follow best practices for Java programming. By following these steps, you can become a proficient Java developer and write efficient, readable, and maintainable code.

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How do I run a Java program on Terminal (Mac)?

I am new to Java (as of today!) and am trying to run a very simple program in terminal. Normally, when I run a python (still pretty new) program in Terminal I would simple type in «python name.py» in to terminal and it would run. When I type «Java name.java» it does absolutely nothing. I opened TextWrangler and selected «Run in Terminal» and it returned this error: «This file doesn’t appear to contain a valid ‘shebang’ line (application error code: 13304)» My program is named «hello.java» and it contains the code below. What am I doing wrong?

3 Answers 3

Open the terminal, go to the directory where the file is located and do this:

javac -classpath . name.java // compile the code java name // run the program 

Of course, both javac and java must be available in the operating system’s PATH variable, but in a Mac that’s already configured.

Apparently I’m just dense. I went to the directory and typed: javac -classpath.hello.java java hello I tried to type java hello on a new line but terminal obviously tries to run when I hit enter.

@Moose What’s the question? you’re describing the normal behavior. You have to press enter after each line, so the command executes

I typed in: javac -class.hello.java and hit enter. Terminal returned «Unrecognized option: -classpath.hello.java Error: Could not create the Java Virtual Machine. Error: Afatal exception has occurred. Program will exit.»

@Moose type the command exactly as it is in my answer (just replace the name of the class), of course it fails: you wrote something different.

@Moose Then read the rest of my answer: the commands must be in the PATH variable of the operating system. It’s time to read the documentation.

javac helloworld.java java helloworld 

The first line calls the compiler and compiles it in the current directory then the next line runs it

«Run in terminal» attempts to run the software as an interpreted script. On UNIX-like systems (meaning almost everything except Windows), a shebang line is used to indicate, what interpreter is to be used. It consists of the characters #! followed by the command to invoke the interpreter (e.g. #!/usr/bin/python or #!/usr/bin/ruby ). However, Java is not (only) interpreted.

java only runs compiled Java bytecode, so it does not work on source files

Instead, head over to the terminal yourself, compile the code with javac and run the resulting bytecode (the .class files) with java :

javac the_file_name.java java the_class_name 

where the_file_name.java is the file containing main(. ) and the_class_name is the name of the class containing main(. ) (this should usually be the same as the_file_name )

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