Compiling and running a Java application on Mac OSX, or any major operating system, is very easy. Apple includes a fully-functional Java runtime and development environment out-of-the-box with OSX, so all you have to do is write a Java program and use the built-in tools to compile and run it.
Writing Your First Program
The first step is writing a simple Java program. Open up a text editor (the built-in TextEdit app works fine), type in the following code, and save the file as "HelloWorld.java" in your home directory.
public class HelloWorld {
public static void main(String args[]) {
System.out.println("Hello World!");
}
}
For example, if your username is David, save it as "/Users/David/HelloWorld.java". This simple program declares a single class called HelloWorld, with a single method called main. The main method is special in Java, because it is the method the Java runtime will attempt to call when you tell it to execute your program. Think of it as a starting point for your program. The System.out.println() method will print a line of text to the screen, "Hello World!" in this example.
Using the Compiler
Now that you have written a simple Java program, you need to compile it. Run the Terminal app, which is located in "Applications/Utilities/Terminal.app". Type the following commands into the terminal:
cd ~
javac HelloWorld.java
You just compiled your first Java application, albeit a simple one, on OSX. The process of compiling will produce a single file, called "HelloWorld.class". This file contains Java byte codes, which are the instructions that the Java Virtual Machine understands.
Running Your Program
To run the program, type the following command in the terminal.
java HelloWorld
This command will start a Java Virtual Machine and attempt to load the class called HelloWorld. Once it loads that class, it will execute the main method I mentioned earlier. You should see "Hello World!" printed in the terminal window. That's all there is to it.
As a side note, TextWrangler is just a text editor for OSX and has no bearing on this situation. You can use it as your text editor in this example, but it is certainly not necessary.
Answer from William Brendel on Stack OverflowCompiling and running a Java application on Mac OSX, or any major operating system, is very easy. Apple includes a fully-functional Java runtime and development environment out-of-the-box with OSX, so all you have to do is write a Java program and use the built-in tools to compile and run it.
Writing Your First Program
The first step is writing a simple Java program. Open up a text editor (the built-in TextEdit app works fine), type in the following code, and save the file as "HelloWorld.java" in your home directory.
public class HelloWorld {
public static void main(String args[]) {
System.out.println("Hello World!");
}
}
For example, if your username is David, save it as "/Users/David/HelloWorld.java". This simple program declares a single class called HelloWorld, with a single method called main. The main method is special in Java, because it is the method the Java runtime will attempt to call when you tell it to execute your program. Think of it as a starting point for your program. The System.out.println() method will print a line of text to the screen, "Hello World!" in this example.
Using the Compiler
Now that you have written a simple Java program, you need to compile it. Run the Terminal app, which is located in "Applications/Utilities/Terminal.app". Type the following commands into the terminal:
cd ~
javac HelloWorld.java
You just compiled your first Java application, albeit a simple one, on OSX. The process of compiling will produce a single file, called "HelloWorld.class". This file contains Java byte codes, which are the instructions that the Java Virtual Machine understands.
Running Your Program
To run the program, type the following command in the terminal.
java HelloWorld
This command will start a Java Virtual Machine and attempt to load the class called HelloWorld. Once it loads that class, it will execute the main method I mentioned earlier. You should see "Hello World!" printed in the terminal window. That's all there is to it.
As a side note, TextWrangler is just a text editor for OSX and has no bearing on this situation. You can use it as your text editor in this example, but it is certainly not necessary.
I will give you steps to writing and compiling code. Use this example:
public class Paycheck {
public static void main(String args[]) {
double amountInAccount;
amountInAccount = 128.57;
System.out.print("You earned $");
System.out.print(amountInAccount);
System.out.println(" at work today.");
}
}
- Save the code as
Paycheck.java - Go to terminal and type
cd Desktop - Type
javac Paycheck.java - Type
java Paycheck - Enjoy your program!
macos - How do I run a Java program on Terminal (Mac)? - Stack Overflow
How do I compile a program via terminal on macbook?
macos - How to run a Java program from mac terminal? - Stack Overflow
macos - How to run a Java Class in Terminal - Stack Overflow
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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.
Type
javac helloworld.java
java helloworld
The first line calls the compiler and compiles it in the current directory then the next line runs it
SOLVED
Hello All. I'm new to programming and java. I'm trying to compile a program via terminal on a macbook and I keep running into errors. I was wondering what I need to change to fix this issue. First I changed the directory of my terminal to the folder that has the .java program in it. I ran "ls" to verify that my .java program was in that directory and it was. However, when I run javac Planet.java I get 60+ errors. This is just a small trial code nothing elaborate. Further info: I have had no issues compiling this code when using an online compiler called CodingGround found here: https://www.tutorialspoint.com/compile_java_online.php I just seem to have issues when using the terminal.
Here is my code (I removed spaces in case I had invisible characters that were causing me issues):
class Planet{
void revolve(){
System.out.println("Revolve");
}
public static void main(String[] args){
Planet earth = new Planet();
earth.revolve();
}
}
I have also tried making it a "public" class by changing the first line to public class Planet{ and still run into the same issues.
Picture of Errors Here:
https://postimg.cc/qNGHhnPk
https://postimg.cc/QK7RXWgZ
PS: Solution: was solved by thisisjustascreename: The text editor is the problem. Macbook's default TextEdit.app dose not automatically save in plain text. You have open the file and go to Format up at the top and then click on Make Plain Text and after saving it and making sure it is still just a .java file and run it via terminal with the javac command it will work just fine.
cd into the directory in which your Calculator.java file is stored, run
javac Calculator.java
this will create a file Calculator.class. You can now run the compiled class with
java Calculator
mind that there is no .class to be added!
The online docs should be your first recourse: https://docs.oracle.com/javase/8/docs/technotes/tools/unix/java.html which tell us that the command line is
java [options] classname [args]
In more depth, and linked from somewhere on that page, you can read https://docs.oracle.com/javase/8/docs/technotes/tools/unix/classpath.html#CBHHCGFB
which is applicable to pretty much all the Java tools. These docs contain the answer to your question. You can either cd into the directory that is the root of your classpath and use the default classpath, as one answer suggested, or use the classpath options described in the docs to set the directory(-ies) at the top of your classpath. E.g.,
java -cp /Users/mac/Documents/workspace/Calculator/bin Calculator