"Java not enabled" in deployed app

Question

chris 2020-2-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/505493-java-not-enabled-in-deployed-app

评论： Sabine Eckhardt 2020-3-5

To showcase the issue, consider the following simple function:

function checkJavaVersion
    version -java

When I execute it in Matlab I receive the following result:

>> checkJavaVersion
ans =
    'Java 1.8.0_202-b08 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode'

Now I am using the Matlab Compiler to deploy this function:

mcc -m checkJavaVersion.m

And I execute it in a machine (the same one that built the function) with the Matlab Runtime installed:

./run_checkJavaVersion.sh /usr/local/MATLAB/MATLAB_Runtime/v97

And here is the response:

------------------------------------------
Setting up environment variables
---
LD_LIBRARY_PATH is .:/usr/local/MATLAB/MATLAB_Runtime/v97/runtime/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v97/bin/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v97/sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v97/sys/opengl/lib/glnxa64
ans =
    'Java is not enabled'

How could Java be enabled in such a scenario?

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chris 2020-2-14

I should also point out that this was tested on Ubuntu 19.10.

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Answer 1

chris 2020-2-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/505493-java-not-enabled-in-deployed-app#answer_415963

在 MATLAB Online 中打开

In case anyone else encounters this issue of JVM not being available in compiled Matlab apps (e.g. due to compiling p-coded files) here is the solution:

From Matworks support:

"MATLAB Compiler, during the dependency analysis, actually tries to determine whether your application requires Java or not. If the analysis concludes your application does not require Java, Java support is indeed automatically disabled when you run the application, this is expected behavior; this increases startup performance and reduces resource (mainly memory) usage."

So in the aforementioned example one should modify the function to include a command that requires Java, e.g.:

function checkJavaVersion
  % Actually do something using Java
  javaString = java.lang.String('myString');
  version -java

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Sabine Eckhardt 2020-3-4

I think I am having exactly the same problem, however use R2019a and I get in the end not a succeed, but following message:

------------------------------------------

Setting up environment variables

---

LD_LIBRARY_PATH is .:/usr/local/MATLAB/MATLAB_Runtime/v96//runtime/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v96//bin/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v96//sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v96//sys/opengl/lib/glnxa64

Undefined variable "java" or class "java.lang.String".

Error in checkjava (line 2)

MATLAB:undefinedVarOrClass