loading file twice locks the file

[yikes aroni]

done.  internal review ID : 9052500

thanks

On Fri, Feb 2, 2018 at 7:00 AM, <nashorn-dev-request at openjdk.java.net>
wrote:

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> Today's Topics:
>
>    1. loading file twice locks the file (yikes aroni)
>    2. Re: loading file twice locks the file
>       (Sundararajan Athijegannathan)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 1 Feb 2018 08:19:14 -0500
> From: yikes aroni <yikesaroni at gmail.com>
> To: nashorn-dev at openjdk.java.net
> Subject: loading file twice locks the file
> Message-ID:
>         <CAEFKuY=S+8GOmxN6RQAB=Su3Aid8bvw9T9N78-Us7CdsNEaijw at mail.
> gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> I find that, when i load a javascript file in java *twice *using this
> pattern
>
> ScriptObjectMirror som = scriptEngine.eval("load('c:/temp/test.js');");
>
>
> it locks the JS file (prevents its deletion). This does NOT happen if i
> load the file only once. Furthermore, this happens even if i null out the
> resulting ScriptObjectMirrors. My question is: how can I avoid this? I need
> to be able to load the file and get the resulting ScriptObjectMirror
> multiple times and be able to delete the source file.
>
> Is Nashorn not properly closing a stream?  It's odd that it doesn't lock
> the file for the first SOM, but does for the second (and subsequent)
> SOMs....
>
> Try it with this code. Instructions:
>
> 1) Create a file "test.js" and put it where you want. I put it in
> c:\temp\test.js
>
> (function(module) {
> var exports = module.exports;
> exports.test = function() {
> return "test ok";
> }
> return module.exports;})({exports:{}, id:'test'});
>
>
> 2)  Create a Temp.java as follows and run it first with *loadSecondSom =
> true*. The deletion will fail. Then run it with *loadSecondSom = false*.
> The deletion will succeed. (Note: the "pause" is only to make it
> clearer...)
>
> import java.io.IOException;
> import java.nio.file.Files;
> import java.nio.file.Path;
> import java.nio.file.Paths;
>
> import javax.script.ScriptEngine;
> import javax.script.ScriptException;
>
> import jdk.nashorn.api.scripting.NashornScriptEngineFactory;
> import jdk.nashorn.api.scripting.ScriptObjectMirror;
>
> public class Temp {
> private static final NashornScriptEngineFactory nashornFactory = new
> NashornScriptEngineFactory();
> private static ScriptEngine scriptEngine = nashornFactory.
> getScriptEngine();
>
> private static void deleteFile(String sPath) throws IOException {
> Path p = Paths.get(sPath);
> Files.delete(p);
> }
> private static void pause(int numsecs) {
> int x;
> try {
> for (int i=0;i<numsecs;i++) {
> Thread.sleep(1000);
> x = i;
> }
> } catch (InterruptedException e) {
> e.printStackTrace();
> }
> }
>
> public static void main(String[] ss) {
> boolean loadSecondSom = true;
> String sPath = "C:/temp/test.js";
> try {
> System.out.println("loading and calling som1...");
> ScriptObjectMirror som1 = (ScriptObjectMirror)scriptEngine.eval("load('" +
> sPath + "');");
> System.out.println(som1.callMember("test"));
> System.out.println("Sleeping ... ");
> pause(2);
> if (loadSecondSom) {
> System.out.println("loading and calling som2...");
> ScriptObjectMirror som2 = (ScriptObjectMirror)scriptEngine.eval("load('" +
> sPath + "');");
> System.out.println(som2.callMember("test"));
> }
>
> System.out.println("Sleeping ... ");
> pause(2);
>
> System.out.println("Attempting to delete the file from the fs...");
> try {
> deleteFile(sPath);
> } catch (IOException e) {
> System.out.println("Cannot delete the file: "+e);
> }
>
> System.out.println("DONE");
> } catch (ScriptException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> }
> }
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 01 Feb 2018 20:43:15 +0530
> From: Sundararajan Athijegannathan
>         <sundararajan.athijegannathan at oracle.com>
> To: nashorn-dev at openjdk.java.net
> Subject: Re: loading file twice locks the file
> Message-ID: <5A732E8B.3060306 at oracle.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> Will you please file a bug with test case attached?
>
> Thanks,
> -Sundar
>
> On 01/02/18, 6:49 PM, yikes aroni wrote:
> > I find that, when i load a javascript file in java *twice *using this
> > pattern
> >
> > ScriptObjectMirror som = scriptEngine.eval("load('c:/temp/test.js');");
> >
> >
> > it locks the JS file (prevents its deletion). This does NOT happen if i
> > load the file only once. Furthermore, this happens even if i null out the
> > resulting ScriptObjectMirrors. My question is: how can I avoid this? I
> need
> > to be able to load the file and get the resulting ScriptObjectMirror
> > multiple times and be able to delete the source file.
> >
> > Is Nashorn not properly closing a stream?  It's odd that it doesn't lock
> > the file for the first SOM, but does for the second (and subsequent)
> > SOMs....
> >
> > Try it with this code. Instructions:
> >
> > 1) Create a file "test.js" and put it where you want. I put it in
> > c:\temp\test.js
> >
> > (function(module) {
> > var exports = module.exports;
> > exports.test = function() {
> > return "test ok";
> > }
> > return module.exports;})({exports:{}, id:'test'});
> >
> >
> > 2)  Create a Temp.java as follows and run it first with *loadSecondSom =
> > true*. The deletion will fail. Then run it with *loadSecondSom = false*.
> > The deletion will succeed. (Note: the "pause" is only to make it
> clearer...)
> >
> > import java.io.IOException;
> > import java.nio.file.Files;
> > import java.nio.file.Path;
> > import java.nio.file.Paths;
> >
> > import javax.script.ScriptEngine;
> > import javax.script.ScriptException;
> >
> > import jdk.nashorn.api.scripting.NashornScriptEngineFactory;
> > import jdk.nashorn.api.scripting.ScriptObjectMirror;
> >
> > public class Temp {
> > private static final NashornScriptEngineFactory nashornFactory = new
> > NashornScriptEngineFactory();
> > private static ScriptEngine scriptEngine = nashornFactory.
> getScriptEngine();
> >
> > private static void deleteFile(String sPath) throws IOException {
> > Path p = Paths.get(sPath);
> > Files.delete(p);
> > }
> > private static void pause(int numsecs) {
> > int x;
> > try {
> > for (int i=0;i<numsecs;i++) {
> > Thread.sleep(1000);
> > x = i;
> > }
> > } catch (InterruptedException e) {
> > e.printStackTrace();
> > }
> > }
> >
> > public static void main(String[] ss) {
> > boolean loadSecondSom = true;
> > String sPath = "C:/temp/test.js";
> > try {
> > System.out.println("loading and calling som1...");
> > ScriptObjectMirror som1 = (ScriptObjectMirror)scriptEngine.eval("load('"
> +
> > sPath + "');");
> > System.out.println(som1.callMember("test"));
> > System.out.println("Sleeping ... ");
> > pause(2);
> > if (loadSecondSom) {
> > System.out.println("loading and calling som2...");
> > ScriptObjectMirror som2 = (ScriptObjectMirror)scriptEngine.eval("load('"
> +
> > sPath + "');");
> > System.out.println(som2.callMember("test"));
> > }
> >
> > System.out.println("Sleeping ... ");
> > pause(2);
> >
> > System.out.println("Attempting to delete the file from the fs...");
> > try {
> > deleteFile(sPath);
> > } catch (IOException e) {
> > System.out.println("Cannot delete the file: "+e);
> > }
> >
> > System.out.println("DONE");
> > } catch (ScriptException e) {
> > // TODO Auto-generated catch block
> > e.printStackTrace();
> > }
> > }
> > }
>
>
> End of nashorn-dev Digest, Vol 63, Issue 1
> ******************************************
>