Vim - When I run my Java file, the println statements don't seem to be getting executed

Question

I'm using GVim. I created a file caled InsertionSort.java and this is what is inside the file:

public class InsertionSort {
    public static void main (String[] args) {
        System.out.println("Hello World");
    }
}

I then opened up terminal and did

sudo apt-get install default-jdk

to install javac. Next, I went back to GVim and did:

:!javac %

to run the current file. When I did this, it said:

!javac /Documents/Java/InsertionSort.java
Press ENTER or type command to continue

and when I press ENTER, it goes back to InsertionSort.java. It doesn't print anything. I looked at this post: Compiling Java code in Vim more efficiently and the highest rated answer said to add these to my .vimrc file:

autocmd Filetype java set makeprg=javac\ %
set errorformat=%A%f:%l:\ %m,%-Z%p^,%-C%.%#
map <F9> :make<Return>:copen<Return>
map <F10> :cprevious<Return>
map <F11> :cnext<Return>

After adding the above lines to my .vimrc file, I reopend GVim / InsertionSort.java and pressed F9 and it said:

!javac Documents/Java/InsertionSort.java 2>&1| tee /tmp/vcqcE1x/8

:copen

Press ENTER or type command to continue

and when I pressed ENTER, it opened up a new GVim file called:

[Quickfix List] :javac Documents/Java/InsertionSort.java

and the file did not have anything in it (It didn't say "Hello World"). How do I make it run the file so that it displays "Hello World"?

Answer 1

I think you may be mixing up the java and javac programs. javac compiles *.java source files into *.class bytecode files. java takes compiled *.class bytecode files and runs them. So if your goal is to compile and run a file called Example.java, you'll need to do this:

javac Example.java
java Example