Create a Java Package with MATLAB Code Error

I follow the following example:

https://www.mathworks.com/help/compiler_sdk/gs/create-a-java-application-with-matlab-code.html#

In this step,

Compile the Java application using javac.

javac -classpath "mcrroot\toolbox\javabuilder\jar\javabuilder.jar";.\makesqr.jar .\getmagic.java

The cmd prompted the error :

.\getmagic.java:4: error: error while writing getmagic: C:\Program Files\makesqr\application\getmagic.class class getmagic ^ 1 error

Answer 1

[Kojiro Saito]

This is due to file access permissions. In my case, I got the following error.

C:\Program Files\makesqr\application>javac -classpath "C:\MATLAB\MATLAB_Runtime\v94\toolbox\javabuilder\jar\javabuilder.jar";.\makesqr.jar .\getmagic.java
.\getmagic.java:4: error: error while writing getmagic: .\getmagic.class (Access is denied)
class getmagic
^
1 error

javac tries to create getmagic.class file, but normal users do not have a permission to write a file under C:\Program Files.

I think there are two options.

1. Launch command prompt as Administrator, then execute the javac command.
2. Install makesqr package in another folder where normal users have a permission to write

[ABHISHEK BHARDWAJ]

On my system it is saying

error: file not found: .\getmagic.java

Please tell me why?

[Kojiro Saito]

getmagic.java is to be created by yourself. In documentation of R2018b or earlier, you can find getmagic.java sample in "Java Code to Implement Application".

https://www.mathworks.com/help/releases/R2018b/compiler_sdk/gs/create-a-java-application-with-matlab-code.html

From R2019a, the java code is included in for_redistribution_files_only\samples folder.

[ABHISHEK BHARDWAJ]

Thank you for the reply, I have followed the process given in the link.

While installing MaAppInstaller_mcr.exe following error occurs :

Internal error: Failed to initialize application installer (204)

I am using MATLAB 2018a.

[ABHISHEK BHARDWAJ]

I am using matlab 2018a. After following the full process of following link

https://www.mathworks.com/help/releases/R2018b/compiler_sdk/gs/create-a-java-application-with-matlab-code.html

in the last step of executing following command ->

F:\makesqr\for_redistribution_files_only>java -classpath .;"C:\Program Files\MAT

LAB\MATLAB Runtime\v94\toolbox\javabuilder\jar\javabuilder.jar";.\makesqr.jar ge

tmagic 5

this error is generated ->

Error: A JNI error has occurred, please check your installation and try again

Exception in thread "main" java.lang.UnsupportedClassVersionError: getmagic has

been compiled by a more recent version of the Java Runtime (class file version 5

5.0), this version of the Java Runtime only recognizes class file versions up to

52.0

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(Unknown Source)

at java.security.SecureClassLoader.defineClass(Unknown Source)

at java.net.URLClassLoader.defineClass(Unknown Source)

at java.net.URLClassLoader.access$100(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

How this error can be resolved?

[Kojiro Saito]

The class file version is 55.0, so I guess you have compiled getmagic.java by Java 11.

JVM in MATLAB R2018a (MATLAB Runtime v94) is Java 1.8.0_144, so you need to do javac by Java 8.

[ABHISHEK BHARDWAJ]

Thank you very much...It worked...