How to get classpath in Groovy?

Question

How can I get current value of CLASSPATH in Groovy?

score 17 · Answer 1 · answered Nov 25 '14 at 16:02

Shameless stolen from http://blog.blindgaenger.net/print_groovys_classpath_for_debugging.html This code will go up the classloader tree and printout each classloader and the associated classpath.

def printClassPath(classLoader) {
  println "$classLoader"
  classLoader.getURLs().each {url->
     println "- ${url.toString()}"
  }
  if (classLoader.parent) {
     printClassPath(classLoader.parent)
  }
}
printClassPath this.class.classLoader

score 3 · Answer 2 · answered Jun 05 '12 at 16:20

3

You should be able to get the classpath from the SystemClassLoader, providing it is an URLClassLoader:

URL[] classPathUrls = ClassLoader.getSystemClassLoader().getURLs();

answered Jun 05 '12 at 16:20

Edvin Syse

7,267
18
24

1

Same thing: both the `CLASSPATH` environment variable and the `-classpath` in the command line have no effect on this list. At least in my case it is identical to what I see in the property `java.class.path`. – Sergey Orshanskiy Oct 11 '13 at 20:21
1

However, see http://groovy.codehaus.org/How+can+I+dynamically+add+a+library+to+the+classpath about dynamically adding a path to classpath. this.class.classLoader.rootLoader.addURL( new URL("file:///d:/drivers/ojdbc14.jar") ) – Sergey Orshanskiy Oct 11 '13 at 20:39

score 1 · Answer 3 · answered Oct 11 '13 at 20:16

java.class.path doesn't work properly, at least in Groovy 2.1.6 (Mac OS X 10.6.8).

HelloWorld.groovy:

public class HelloWorld {

    public static void main(def args) {
        System.out.println( "Hello, world!\n");
        System.out.println(System.getenv("CLASSPATH")+"\n");
        System.out.println(System.getProperty("java.class.path"));
    }
}

Then

export CLASSPATH=/etc
groovy -classpath /usr HelloWorld.groovy

Result:

Hello, World!

/etc

/Applications/groovy-2.1.6/lib/groovy-2.1.6.jar

Now, this is HelloWorld.java: (I had to change it a bit as Groovy and Java are not 100% compatible):

public class HelloWorld {
    public static void main(String args[]) {
         System.out.println( "Hello, world!\n");
         System.out.println(System.getenv("CLASSPATH")+"\n");
        System.out.println(System.getProperty("java.class.path"));
    }
}

Now:

javac HelloWorld.java
export CLASSPATH=/etc
java -classpath /usr HelloWorld

Result:

Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld
Caused by: java.lang.ClassNotFoundException: HelloWorld
etc. ...................

Then:

java -classpath /usr:. HelloWorld

Result:

Hello, world!

/etc

/usr:.

I'll update if I find out how to make it work in Groovy...

score 0 · Accepted Answer · answered Mar 06 '11 at 18:21

0

This doesn't work?

System.getProperty('java.class.path')

answered Mar 06 '11 at 18:21

Tomasz Nurkiewicz

334,321
69
703
674

3

It's empty :( Is it possible to get classpath form class loader? – yegor256 Mar 06 '11 at 18:53
3

Groovy seems to do funky stuff, and the java.class.path does not contain the classpath passed with groovy's -cp command line option. – Egon Willighagen Sep 20 '11 at 12:41
2

It shows only groovy jar - why http://stackoverflow.com/a/27131375/1042297 is not accepted answer ? – kodstark Aug 12 '16 at 17:13

score 0 · Answer 5 · answered Oct 29 '11 at 07:07

Get the CLASSPATH and files if you want in the those CLASSPATH if needed you can view it

System.getProperty("java.class.path", ".").tokenize(File.pathSeparator).each {
                               println it                             
                }

score -1 · Answer 6 · answered Mar 06 '11 at 18:21

-1

def classpath = System.properties["java.class.path"]

answered Mar 06 '11 at 18:21

Bozho

588,226
146
1,060
1,140

Unfortunately it's empty when I'm using Groovy inside [gmaven plugin](http://docs.codehaus.org/display/GMAVEN/Executing+Groovy+Code). Is it possible to get classpath from class loader somehow? – yegor256 Mar 06 '11 at 18:55

How to get classpath in Groovy?

6 Answers6

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