Execute java file and get output from cmd

Question

I want to compile second file and get the output but it throw an Exception .

  public static void main(String[] args) throws IOException, InterruptedException {

    String path="C:\\Users\\Amr\\Documents\\NetBeansProjects\\Second.java";   

    Process pro1 = Runtime.getRuntime().exec("javac " + path);

    ProcessBuilder ps = new ProcessBuilder("java ", path);

    ps.redirectErrorStream(true);

    Process pr = ps.start();

    BufferedReader in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
    String line;
    while ((line = in.readLine()) != null) {
        System.out.println(line);
    }
    pr.waitFor();
    System.out.println("ok!");

    in.close();

    pro1.waitFor();

}

Get output from this class

public class Second {
public static void main(String[] args) {
    System.out.println("Hello world from Second.java");
}}

please any help for repairing the errors

that is the error

Error: Could not find or load main class C:\Users\Amr\Documents\NetBeansProjects\Second.java

What errors are you getting? And why do you have two main methods? — jiaweizhang
– jiaweizhang, Commented Jan 29, 2016 at 2:18
In which class is the first main method located? Still wondering why you have two main methods. — jiaweizhang
– jiaweizhang, Commented Jan 29, 2016 at 2:23
It looks like you're attempting to load "Second.java" as a class file. Try replacing Second.java with Second.class — z7r1k3
– z7r1k3, Commented Jan 29, 2016 at 2:23
@jiaweizhang i want to get output Second class (external class not has a relation with another class ) from cmd — Amr Emaish
– Amr Emaish, Commented Jan 29, 2016 at 2:32

Saravana · Accepted Answer · 2016-01-29 03:38:27Z

2

 ProcessBuilder ps = new ProcessBuilder("java ", path);

You're executing java Second.java it should be java Second

replace path.replace(".java","") or create a variable without ".java"

nsaravanas@ubuntu:~$ pwd
/home/nsaravanas
nsaravanas@ubuntu:~$ javac com/test/Second.java
nsaravanas@ubuntu:~$ java com.test.Second
Hello world from Second.java
nsaravanas@ubuntu:~$

edited Jan 29, 2016 at 3:38

answered Jan 29, 2016 at 3:00

Saravana

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1 Comment

Saravana Over a year ago

do your class have package? I've edited my answer,could you check?

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