Library compiler java package error

I am trying to use the library compiler to generate a java package for matlab functions. And I select all the functions with an existing sample.

But I am facing the below error and no files are generated in xxxx/for_redistribution_files_only\samples.

com.mathworks.mvm.exec.MvmExecutionException: compiler.internal.ExampleParser.getArgumentValidation

at com.mathworks.mvm.exec.NativeFutureResult.nativeGet(Native Method)

at com.mathworks.mvm.exec.NativeFutureResult.get(NativeFutureResult.java:62)

at com.mathworks.mvm.exec.FutureResult.getInternal(FutureResult.java:413)

at com.mathworks.mvm.exec.FutureFevalResult.getInternal(FutureFevalResult.java:49)

at com.mathworks.mvm.exec.FutureResult.get(FutureResult.java:263)

at com.mathworks.toolbox.compiler_examples.generation.ExampleValidator.validateExample(ExampleValidator.java:41)

at com.mathworks.toolbox.compiler.plugin.PackageCommand$3.iterate(PackageCommand.java:416)

at com.mathworks.project.impl.plugin.XmlReaderImpl.loop(XmlReaderImpl.java:232)

at com.mathworks.toolbox.compiler.plugin.PackageCommand.packageSamples(PackageCommand.java:409)

at com.mathworks.toolbox.compiler.plugin.PackageCommand.execute(PackageCommand.java:676)

at com.mathworks.project.impl.engine.DeploymentEngine.executeScript(DeploymentEngine.java:373)

at com.mathworks.project.impl.engine.DeploymentEngine.access$000(DeploymentEngine.java:44)

at com.mathworks.project.impl.engine.DeploymentEngine$2.run(DeploymentEngine.java:289)

at java.lang.Thread.run(Thread.java:748)

Caused by: com.mathworks.mvm.exec.MvmRuntimeException: Reference to a cleared variable this.

Error in ==> C:\Program Files\MATLAB\R2020b\toolbox\compiler_sdk\java\+compiler\+internal\ExampleParser.p>ExampleParser.getVariables at 0

Error in ==> C:\Program Files\MATLAB\R2020b\toolbox\compiler_sdk\java\+compiler\+internal\ExampleParser.p>ExampleParser.getArgumentValidation at 0

Answer 1

[Kojiro Saito]

I can reproduce this issue if sample m script contains clear all.

Reproduction Step

addmatrix.m (to be compiled as Java package)

function out = addmatrix(in1, in2)
    out = in1 + in2;
end

addmatrixWithClearSample2.m (sample m file which calls addmatrix)

clear all;
in1 = 0; % Initialize in1 here
in2 = 0; % Initialize in2 here
out = addmatrix(in1, in2);

Add addmatrixWithClearSample2.m from "Add Existing Sample" in Samples panel of Library Compiler window.

When packaging, we'll get "Caused by: com.mathworks.mvm.exec.MvmRuntimeException: Reference to a cleared variable this." error as you provided.

Solution

Remove or comment out "clear all" in your sample script. In the above example, addmatrixWithClearSample2.m should be the following.

addmatrixWithClearSample2.m

%clear all; % Comment out
in1 = 0; % Initialize in1 here
in2 = 0; % Initialize in2 here
out = addmatrix(in1, in2);

[CHV]

Thanks for the solution. After removing the clear all I am not facing this issue.

[CHV]

I am requesting you to Can you please have a look in the below issue and provide me the solution for this one also.

https://de.mathworks.com/matlabcentral/answers/874368-error-during-sample-generation-of-java-pacakage-using-library-compiler

Thanks in advance