- COMPILING JAVA FROM COMMAND LINE HOW TO
- COMPILING JAVA FROM COMMAND LINE CODE
- COMPILING JAVA FROM COMMAND LINE MAC
These automatic compilations are nested, and this continues until all classes are compiled that are needed to run the program. In Java, if you have used any reference to any other java object, then the class for that object will be automatically compiled, if that was not compiled already.
Automatic Compilation of Dependent Classes The above command should result in your command-line application displaying the following result:Īsk for help if the program did not execute properly in the Discussion page for this chapter. If you obtain an error message like Exception in thread "main" : main, your source file may have been badly written. If you obtain an error message like Exception in thread "main" : HelloWorld, the HelloWorld.class file is not in the current folder or it is badly spelled. Once the compiler returns to the prompt, run the application using the following command: Are you launching the javac program correctly? If no HelloWorld.class file has been created in the same folder, then you've got an error. If your computer emits beeps, then you may have illegal characters in your HelloWorld.java. Are you sure all words are spelled correctly and with the exact case as shown? Are there semicolons and brackets in the appropriate spot? Are you missing a quote? Usually, modern IDEs would try coloring the entire source as a quote in this case. errors, there may be a mistake in your code. If you obtain another message ending by 1 error or. Did you navigate to the program's location in the command prompt using the cd ( change directory) command? If you obtain an error message like error: cannot read: HelloWorld.java 1 error, your file is not in the current folder or it is badly spelled.
COMPILING JAVA FROM COMMAND LINE HOW TO
If you do not know how to do this, consider reading through our crash courses for command-line applications for Windows or Linux.Ĭompile the Java source file using the following command which you can copy and paste in if you want: In your command-line application, navigate to the directory where you just created your file.
COMPILING JAVA FROM COMMAND LINE MAC
Next, open your preferred command-line application.įor example, Command Prompt on Windows and, Terminal on Linux and Mac OS. This name is case-sensitive, which means you need to capitalize the precise letters that were capitalized in the name for the class definition. Save the file as HelloWorld.java - the name of your file should be the same as the name of your class definition and followed by the.
COMPILING JAVA FROM COMMAND LINE CODE
Write the following lines of code in a new text document: Open your preferred text editor - this is the editor you set while installing the Java platform.įor example, Notepad or Notepad++ on Windows Gedit, Kate or SciTE on Linux or, XCode on Mac OS, etc. Proceed only if you have successfully installed and configured your system for Java as discussed here. To execute your first Java program, follow the instructions below: This is different from other languages like C/C++ where programs are to be compiled to machine code and linked to create an executable file before it can be executed. The Java classes/bytecode are compiled to machine code and loaded into memory by the JVM when needed the first time.
The bytecode gets saved on the disk with the file extension. Java source code is compiled into bytecode when we use the javac compiler. In Java, programs are not compiled into executable files they are compiled into bytecode (as discussed earlier), which the JVM (Java Virtual Machine) then executes at runtime.