Thread: JavaCompiler is not finding the file

Originally Posted by Norm

Your code works for me with java 1.7. It doesn't find the JavaCompiler with java 1.8.


Where does the part in Red come from? It is not in the code.
.

That is the path, the file is found in; I changed my name and the folders name for this post.
I compiled it again, and it seems, to be my fault; why did I insert the (in your post) red part, into this thread, when it is not in the compiler? Sorry for that: :-(

So here's the error message again:

javac: file not found: test.java
Usage: javac <options> <source files>
use -help for a list of possible options

So you mean, I should use Java 1.7?

Originally Posted by Norm

It is better when the posted code and the posted error messages are in synch.

Eh...sorry, don't quite understand what you mean with posting them in synch.

Originally Posted by Norm

No. Your code is not getting the error I was: compiler was null.
I have not tracked down why my the compiler variable is null with the default java command on my system. The code works with all the other java commands I've tested with.

Shall I use another command to run the script?

Originally Posted by Norm

What happens if you manually use the javac command to compile test.java?

If I run it manually, through the command line, nothing happens, but if I run it using the Java "Runner" from VS Code, in my Editor, it is opening up a GUI Window (and that's what it's supposed to do).

First of all, I created a new folder, and I put both the scripts, the actual compiler script and the test file in there.

I then added this, to the test file, and got that error:

error: cannot find symbol
    static File file = File("C:\\Hilfsassistent\\main.java");
                       ^
  symbol:   method File(String)
  location: class main
1 error

import java.io.File;
 
public class main{
    public static void main(String[] args) {
        pathname();
    } 
 
public static String pathname() {
        static File file = File("C:\\Hilfsassistent\\test.java");
        System.out.println("Path : " + file.getAbsolutePath());
    }

But when I compile it, it tells me, that it is not finding the file (As mentioned above).

Next up I tried adding one line of code.
But it doesn't seem to be useful, because it prints the following:

Working Directory = /

That's what I'm talking about:

System.out.println("Working Directory = " + System.getProperty("user.dir"));

Thanks for your help.

I get the following error here:

error: cannot find symbol
        File aFile = new File("test.java");
        ^
  symbol:   class File
  location: class javaCompilera
/Users/myusername/T/javaCompilera.java:14: error: cannot find symbol
        File aFile = new File("test.java");
                         ^
  symbol:   class File
  location: class javaCompilera
2 errors

What do I need to import, that it knows this object type?
Can't I just somewhere in the following line, give the program a path?

int result = compiler.run(null, null, null, "test.java");

public static void main(String[] args) {  
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        System.out.println(compiler);
        //int result = compiler.run(null, null, null, "test.java");   
        File aFile = new File("test.java");

Thanks for your help.

Originally Posted by Norm

Look at the API documentation for the java SE classes: https://docs.oracle.com/javase/8/docs/api/index.html
Find the class in the lower left frame, click on it and the API doc for the class will be shown in the main frame.
The package the class is in is shown near the top left.

Sorry :-( ; there are so many classes; could you just tell me the name of the class I am looking for? Otherwise it would be kind of hard to find... Thanks :-)

Yes, thanks, I don't get that error anymore, but how can I now locate the path of the file, where the program looks for it, using the

File aFile = new File("test.java");

part?

I did it like this now, and it says, that the Working Directory is null.

Working Directory = null
Path : /test.java

That's the code:

public static void main(String[] args) {  
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        //int result = compiler.run(null, null, null, "test.java");   
        File aFile = new File("test.java");
        System.out.println("Working Directory = " + System.getProperty("test.java"));
 
        //File file = new File("C:\\userName\\T\\test.java");
        System.out.println("Path : " + aFile.getAbsolutePath());

What can I do, because it says it is null. ?

it seems like it's printing out at the path; whatever I put into the "" in the new File(""); part:

Output:

Path : /C:\T\test.java

My Code;

public static void main(String[] args) {  
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        System.out.println(compiler);
        //int result = compiler.run(null, null, null, "test.java");   
        File aFile = new File("test.java");
        System.out.println("Working Directory = " + System.getProperty("user.dir"));
        //System.out.println("Working Directory = " + System.getProperty("test.java"));
        //System.out.println(aFile);
        System.out.println("Path : " + aFile.getAbsolutePath());
        File file = new File("C:\\T\\test.java");
        System.out.println("Path : " + file.getAbsolutePath());
    }

I'm using a Mac. Do you thing that influences, what I get as a result?

I now copied the right path of the file and pasted it in there. What I get then is this:

com.sun.tools.javac.api.JavacTool@1b6d3586
Working Directory = /
Path : /Users/myname/T/test.java

The code:

public static void main(String[] args) {  
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        System.out.println(compiler);
        File file = new File("/Users/myname/T/test.java");
        //int result = compiler.run(null, null, null, "test.java");   
        int result = compiler.run(null, null, null, "/Users/myname/T/test.java");
        System.out.println("Working Directory = " + System.getProperty("user.dir"));
        System.out.println("Path : " + file.getAbsolutePath());

How can I use my compiler component to print out the errors, it gets form the test.java file (if it has compile errors)?
And why am I getting this error, when I try to replace the

 int result = compiler.run(null, null, null, "/Users/myname/T/test.java");

with this:

 int result = compiler.run(null, null, null, file);

The error I am getting when I try that:

error: method run in interface Tool cannot be applied to given types;
        int result = compiler.run(null, null, null, file);
                             ^
  required: InputStream,OutputStream,OutputStream,String[]
  found: <null>,<null>,<null>,File
  reason: varargs mismatch; File cannot be converted to String

Can I somehow write the file variable into the compiler.run function, without having to type in the whole path?

That works fine, but I want the user be able to input a path into a GUI input field, and than that path should get compiled. Do you have any idea how I can achieve that, because I cannot input a String into my compiler.run() function. Also it would be nice to show the errors, from the compiled code (if there are any) in a text label, instead of them getting printed out in the console.
But I don't know how I can do that. Do you have any suggestions there? Would be nice :-)
Thanks

I managed to do that now. Do you have any idea, how I can look in my script, how many (if any) errors I get from compiling the other script, and to than do sth, depending on how many errors the user has in the other script, that got compiled.
I am thinking of an if-function here, but how can I count the errors in the script?

I googled it and found out, that the setErr method allows me to write the errors from the console into e.g. a text file.
What I was thinking of, is that it counts how many errors you got, e.g. somehow like that (using a command, but I don't know which one):

//the variable errorNumbers is just a placeholder for what a command from an import would do
int errorNumbers = 0;
 
//now here I need a method that checks, how many errors you got, from compiling a script with the java command
 
if(errorNumbers == 0) {
System.out.println("You got 0 errors"!);
} else if (errorNumbers <= 3) {
System.out.println("You got three errors or less!");
} else { System.out.println("You got more than three errors!"); }

I don't want to use the things, that the javac command is printing out in the console, I want it to check how many errors I got, from compiling that script.