MATLAB retaining control of JAR file

Hi,

I'm working with java classes and cannot seem to get Matlab to release the JAR files. The only option is to re-start Matlab.

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Simple sample code (java):

    package basicFunctions;

    public class mathFunctions {
      public static int getSqr(int dataInput) {
        return dataInput*dataInput;
      }
    }

Corresponding Matlab code:

    basicFunctions.mathFunctions.getSqr(2)

Result:

    4

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Okay great, it works. What if I re-run with an input of 3?

    9

Things seem to be working as expected. But now if I try to delete my JAR file to use an updated version:

    This action can't be completed because the file is open in MATLAB(R2014b)

I get this error regardless of whether I used the static or dynamic java class path. In the dynamic case, I did remove the paths after use via:

    javaP = javaclasspath('-dynamic');
    javarmpath(javaP{:});

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Other variations on this question

(Aug 2009) Why am I unable to delete or overwrite Java Archive Files (JARs) after using JAVARMPATH to remove them from the Java classpath in MATLAB 7.3 (R2006b)?

    MathWorks Support Team says:

    The ability to explicity unload Java classes is not available in MATLAB.

    MATLAB uses Java's class-loader features to the extent possible to reload new class definitions, 
    while the Java Virtual Machine (JVM) controls when classes get unloaded, and hence whether or not JAR 
    files are released.

    If the objects associated with the JAR files are no longer in use, see the Related Solution listed 
    below about forcing Java garbage collection.

(Oct 2009) Cannot Delete .jar File Used in Matlab

    No solution

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Tried solutions

1) Force java garbage collection

(Jun 2009) How can I request Java garbage collection in the Java Virtual Machine (JVM) in MATLAB 7.3 (R2006b)?

I tried both

     java.lang.System.gc()
     java.lang.Runtime.getRuntime().gc

No luck.

2) Variations on clear

    clear all
    clear java
    clear import
    clear classes

3) fOpen and fClose after use

     With fOpen, fid = 3  -> success
     With fClose, result is 0  -> success

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Other (Potentially) Relevant Details

Yes my compiler is set to the same version as Matlab

[Aaron Wetzler]

This worked for me:

javarmpath ./
javarmpath ./myfile.jar
close all
clear all
fclose all
java.lang.System.gc()
java.lang.Runtime.getRuntime().gc
javaaddpath ./
javaaddpath ./myfile.jar

[Malcolm Lidierth]

If a class reference is still active in the JVM - or has leaked - it will not generally be possible to reload a jar using that class.

Situations that might give rise to a leak include e.g. deleting a variable containing a reference while viewing it in the MATLAB variable inspector.

As an 'orphan' reference may then exist, garbage collection will not work. The reference is reachable within the JVM in principle - so not eligible for collection - but not necassarily by any mechanism available via MATLAB.

Other MATLAB internals might also maintain a reference which I suspect is why TMW say "The ability to explicity unload Java classes is not available in MATLAB."