How do I run a Java program from the command line on Windows?

Question

I\'m trying to execute a Java program from the command line in Windows. Here is my code:

import java.io.File;
import java.io.FileInputStream;
import java.io.         


        

Answer 1

It is easy. If you have saved your file as A.text first thing you should do is save it as A.java. Now it is a Java file.

Now you need to open cmd and set path to you A.java file before compile it. you can refer this for that.

Then you can compile your file using command

javac A.java

Then run it using

java A

So that is how you compile and run a java program in cmd. You can also go through these material that is Java in depth lessons. Lot of things you need to understand in Java is covered there for beginners.

Answer 2

Source: javaindos.

Let's say your file is in C:\mywork\

Run Command Prompt

C:\> cd \mywork

This makes C:\mywork the current directory.

C:\mywork> dir

This displays the directory contents. You should see filenamehere.java among the files.

C:\mywork> set path=%path%;C:\Program Files\Java\jdk1.5.0_09\bin

This tells the system where to find JDK programs.

C:\mywork> javac filenamehere.java

This runs javac.exe, the compiler. You should see nothing but the next system prompt...

C:\mywork> dir

javac has created the filenamehere.class file. You should see filenamehere.java and filenamehere.class among the files.

C:\mywork> java filenamehere

This runs the Java interpreter. You should then see your program output.

If the system cannot find javac, check the set path command. If javac runs but you get errors, check your Java text. If the program compiles but you get an exception, check the spelling and capitalization in the file name and the class name and the java HelloWorld command. Java is case-sensitive!

Answer 3

Now (with JDK 9 onwards), you can just use java to get that executed. In order to execute "Hello.java" containing the main, one can use: java Hello.java

You do not need to compile using separately using javac anymore.

Answer 4

STEP 1: FIRST OPEN THE COMMAND PROMPT WHERE YOUR FILE IS LOCATED. (right click while pressing shift)
STEP 2: THEN USE THE FOLLOWING COMMANDS TO EXECUTE. (lets say the file and class name to be executed is named as Student.java)The example program is in the picture background.

     javac Student.java
     java Student

Answer 5

To complete the answer :

1. The Java File

   TheJavaFile.java
   

2. Compile the Java File to a *.class file

   javac TheJavaFile.java
   

   • This will create a TheJavaFile.class file

3. Execution of the Java File

   java TheJavaFile
   

4. Creation of an executable *.jar file

   • You've got two options here -

     1. With an external manifest file :

        • Create the manifest file say - MANIFEST.mf

        • The MANIFEST file is nothing but an explicit entry of the Main Class

        • jar -cvfm TheJavaFile.jar MANIFEST.mf TheJavaFile.class

     2. Executable by Entry Point:

        • jar -cvfe TheJavaFile.jar <MainClass> TheJavaFile.class

5. To run the Jar File

   java -jar TheJavaFile.jar
   

Answer 6

Since Java 11, java command line tool has been able to run a single-file source-code directly. e.g.

java HelloWorld.java

This was an enhancement with JEP 330: https://openjdk.java.net/jeps/330

For the details of the usage and the limitations, see the manual of your Java implementation such as one provided by Oracle: https://docs.oracle.com/en/java/javase/11/tools/java.html