Hello World (1st Version) Mac OS

broken image


Java and the Mac OS X Terminal


This page is obsolete.

To do this from a shell on Solaris, Linux, or Mac OS X, find the process, and kill it. The server will continue to wait for invocations until it is explicitly stopped. Running the Hello World Application on Two Machines describes one way of distributing the simple application across two machines - a client and a server. SwiftUI 'Hello World' works on iOS, but NOT MacOS. Trying to build a simple 'Hello World' SwiftUI example to see how it works on Mac, but I am getting an empty black screen app. I am using Xcode 11 MacOS target is checked MacOS version 10.15 Beta (19A471t).


This document instructs you on how to use the Mac OS X Terminal with Java.

Java

You will use the Java compiler javac to compile your Java programs andthe Java interpreter java to run them.To verify that Apple's implementation of Java 2 Standard Edition (Java SE 6) isalready installed:

  • Run Software Update.
  • Run Applications/Utilities/Java/Java Preferencesand verify that the Java SE 6 - 64-bit entry is checked andfirst in the list; if not, drag to change the preferred order.
Command-line interface

You will type commands in an application called the Terminal.

  • Open a terminal window. You can find this underGo -> Applications -> Utilities. Drag the Terminal to your dock sinceyou will be using it frequently.
  • You should now have a Terminal window somewhere on the screen.It will have a prompt that looks something like:
  • To check that you are running the right version of Java, typethe commands in boldface below. You should see something similar to the information printed below. The importantpart is that it says 1.6 or 1.5 (and not 1.4).
    Then type
  • Since you will be using the Terminal frequently, you may want tocustomize the default window settings (e.g., Monaco 13pt font with antialiasing).
Hello
Compile the program

You will use the javac command to convert your Java program into a form moreamenable for execution on a computer.

  • From the Terminal, navigate to the directory containing your .javafiles, say ~wayne/introcs/hello, by typing the cd commandbelow.
  • Assuming the file, say HelloWorld.java is in the currentworking directory, type the javac command below to compile it.
    If everything went well, you should see no error messages.
Execute the program

You will use the java command to execute your program.

  • From the Terminal, type the java command below.If all goes well, you should see the output of the program -Hello, World.
Input and Output

If your program gets stuck in an infinite loop, type Ctrl-c to break out.

Hello World (1st Version) Mac Os X

If you are entering input from the keyboard, you can signifyto your program that there is no more data by typingCtrl-d Squarez mac os. for EOF (end of file).You should type this character on its own line.

Hello World (1st Version) Mac Os Pro

Troubleshooting

When I try to run java I get: Exception in thread 'main' java.lang.NoClassDefFoundError.First, be sure that HelloWorld.class is in the current directory.Be sure to type java HelloWorld without a trailing .classor .java.If this was not your problem, it's possiblethat your CLASSPATH was set by some other program so that it no longerincludes the current working directory.Try running your program with the command line

If this works, your classpath is set incorrectly.

I get the error 'class file has wrong version 50.0, should be 49.0' when I compilefrom the Terminal. What does this mean?It's probably because DrJava is configured to use Java 6.0 and and your Terminal is configured to use Java 5.0.To change the default version of Java in your Terminal, launchJava Preferencest. Drag the Java SE 6 - 64-bit entryto appear first.

Hello World (1st Version) Mac Os Download

How do I get the menu to display at the topof the screen instead of at the top of the frame?Execute with java -Dapple.laf.useScreenMenuBar=true

Where can I learn more about the command line?Here is a short tutorial on thecommand-line.





broken image