How can I compile a .java file?
What programs will I need? If I need the Java JDK I will also need help installing that. I'm very new to Ubuntu, so any program that I need to install I will need a tutorial on how to install them.
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Sign up to join this communityTo compile the file, open your terminal and type
javac filename.java
To run the generated class file, use
java filename
But to do this you need to have the Java JDK installed in your computer. You can install it with the instructions in How do I install Java?.
javac java_test.java
finishes successfully, but there is no java_test
file to be found. only a g.class
java filename
it will work, even though the file is not there.
Sep 22, 2017 at 20:23
java.lang.ClassNotFoundException
, try java -cp . filename
.
Sep 5, 2019 at 1:07
OpenJDK works best for me. It's simple and I have never faced any problem with it. Just follow these simple steps:
From Terminal install open jdk
sudo apt-get install openjdk-7-jdk
Write a java program and save the file as filename.java
Now to compile use this command from the terminal
javac filename.java
If everything works well then a new "filename.class" file should be created.
To run your program that you've just compiled type the command below in terminal:
java filename
NOTE
You can use any text editor (like gedit) ,
replace the filename with watever name you want
you need to be on same directory as the "present working directory" (got by running pwd
) while running the command from terminal.
If for example your file is my_file.java
:
class MyClass
{
public static void main(String[] args)
{
System.out.println("Hello World");
}
}
You want to do:
javac my_file.java
and then
java MyClass # The name of the class, not file
However, it is a common convention to give classes and files the same name.
#
is the comment character in shells.
You need to install a JDK, Java Development Kit. Ubuntu contains a metapackage default-jdk, which depends on currently prefered JDK. Now it is openjdk-6-jdk.
To compile a Java file to runnable .class file you can run
javac filename.java
and run it
java file
It is the most simple use-case and mostly it doesn't work because java classes mostly depends on other java classes placed in libraries.
So you would probably like to use some more sophisticated solutions. Most text editors supports Java syntax highlighting, for example jEdit, kate or vim, but they don't solve your compilation issue.
You have another option - you can install a full featured Java IDE. Ubuntu comes with both main OpenSource Java IDEs - NetBeans and Eclipse.
Just type sudo apt-get update
, followed by sudo apt-get install openjdk-7-jdk
for a quick installation for java7, then you can play games with java :-)
For more detailed official Java documentation, please visit this link.
sudo apt-get install openjdk-7-jdk
). Also, it's best to run sudo apt-get update
before install
ing packages from the Terminal.
Jun 3, 2012 at 3:56