Verify if Java is installed from Node.js

Question

I'm building an application that uses Java inside Node.js. I made a Function to check the Java version:

function javaversion() {
    var spawn = require('child_process').spawn('java', ['-version']);
    spawn.stderr.on('data', function(data) {
        data = data.toString().split('\n')[0];
        var javaVersion = new RegExp('java version').test(data) ? data.split(' ')[2].replace(/"/g, '') : false;
        if (javaVersion != false) {
            // TODO: We have Java installed
        } else {
            // TODO: No Java installed
        }
    });
}

But for systems that Java is not installed, Node.js is throwing ENOENT error, because the module "child_process" just can't spawn the process. How can I verify if Java is installed from Node.js?

I appreciate your help!

have you considered checking for an environment variable like classpath or ...? And then looking for the binary? — WiredPrairie
– WiredPrairie, Commented Nov 1, 2013 at 21:42
@WiredPrairie, Yes, I considered, but it is not a good idea to all systems. For example, in OS X 10.8, CLASSPATH is not set. I solved the problem handling the error of not spawning the process, like Sudsy suggested. Thank you. — Formiga
– Formiga, Commented Nov 2, 2013 at 0:09
I've got Java installed (per the Windows installer), but it's not in the path, so this method fails completely. So, doesn't really seem like a good solution for "all systems." — WiredPrairie
– WiredPrairie, Commented Nov 2, 2013 at 1:40

Sudsy · Accepted Answer · 2013-11-01 20:24:09Z

7

What about this?

function javaversion(callback) {
    var spawn = require('child_process').spawn('java', ['-version']);
    spawn.on('error', function(err){
        return callback(err, null);
    })
    spawn.stderr.on('data', function(data) {
        data = data.toString().split('\n')[0];
        var javaVersion = new RegExp('java version').test(data) ? data.split(' ')[2].replace(/"/g, '') : false;
        if (javaVersion != false) {
            // TODO: We have Java installed
            return callback(null, javaVersion);
        } else {
            // TODO: No Java installed

        }
    });
}

javaversion(function(err,version){
    console.log("Version is " + version);
})

answered Nov 1, 2013 at 20:24

Sudsy

9817 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

WhoAmI Over a year ago

How can I check if JDK is installed or not ? If not installed, install it.

felixh Over a year ago

It fails on openjdk. Change the regex from 'java version' to '(java|openjdk) version' to work on openjdk.

Collectives™ on Stack Overflow

Verify if Java is installed from Node.js

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related