Compiling a Matlab Builder for Java class for an older version of Java

[EDIT: 20110610 10:59 CDT - reformat - WDR]

I am running Matlab 2010b and Java 1.6 in my machine, in which I have built a Java class that is used by another program. I need to use this class in multiple versions of that program, including one that supports only Java 1.5 rather than 1.6.

I have changed JAVA_HOME to point to Java 1.5, however I get an error that the javabuilder.jar file is of version 50 rather than 49. Here's the complete compilation log:

ant:

  <mkdir dir="C:\Isight_Krig\development\Krig_matlab\CEDGKrig\distrib" />
  <mkdir dir="C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src" />

mcc -W 'java:CEDGKrig,Krig' -T link:lib -d C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src -w enable:specified_file_mismatch -w enable:repeated_file -w enable:switch_ignored -w enable:missing_lib_sentinel -w enable:demo_license -S -v 'class{Krig:C:\Isight_Krig\development\Krig_matlab\KrigLikelihood.m,C:\Isight_Krig\development\Krig_matlab\KrigPred.m}' 
Compiler version: 4.14 (R2010b) 
Processing include files...
2 item(s) added.
Processing directories installed with MCR...
The file C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\mccExcludedFiles.log contains a list of functions excluded from the CTF archive.
2 item(s) added.
Generating MATLAB path for the compiled application...
Created 44 path items.
Begin validation of MEX files: Fri Jun 10 16:05:08 2011 
End validation of MEX files: Fri Jun 10 16:05:08 2011 
Parsing file "C:\Isight_Krig\development\Krig_matlab\KrigLikelihood.m"
  (Referenced from: "Compiler Command Line"). 
Parsing file "C:\Isight_Krig\development\Krig_matlab\KrigPred.m"
  (Referenced from: "Compiler Command Line"). 
Parsing file "C:\Program Files\MATLAB\R2010b\toolbox\compiler\deploy\deployprint.m"
  (Referenced from: "Compiler Command Line"). 
Parsing file "C:\Program Files\MATLAB\R2010b\toolbox\compiler\deploy\printdlg.m"
  (Referenced from: "Compiler Command Line"). 
Deleting 0 temporary MEX authorization files. 
Generating file "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\readme.txt". 
Executing command: ""C:\Program Files\Java\jdk1.5.0_15\bin\javac" -verbose -classpath "C:\Program Files\MATLAB\R2010b\toolbox\javabuilder\jar\javabuilder.jar" -d "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\classes" "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\Krig.java" "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\CEDGKrigMCRFactory.java" "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\CEDGKrigSharedMCRFactory.java" "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\KrigRemote.java" "C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\package-info.java"" 
[parsing started C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\Krig.java]
[parsing completed 62ms]
[parsing started C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\CEDGKrigMCRFactory.java]
[parsing completed 0ms]
[parsing started C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\CEDGKrigSharedMCRFactory.java]
[parsing completed 0ms]
[parsing started C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\KrigRemote.java]
[parsing completed 0ms]
[parsing started C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\package-info.java]
[parsing completed 0ms]
[search path for source files: [C:\Program Files\MATLAB\R2010b\toolbox\javabuilder\jar\javabuilder.jar]]
[search path for class files: [C:\Program Files\Java\jdk1.5.0_15\jre\lib\rt.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\jsse.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\jce.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\charsets.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\ext\dnsns.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\ext\localedata.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\ext\sunjce_provider.jar, C:\Program Files\Java\jdk1.5.0_15\jre\lib\ext\sunpkcs11.jar, C:\Program Files\MATLAB\R2010b\toolbox\javabuilder\jar\javabuilder.jar]]
[loading C:\Program Files\MATLAB\R2010b\toolbox\javabuilder\jar\javabuilder.jar(com/mathworks/toolbox/javabuilder/internal/MWComponentInstance.class)]
C:\Isight_Krig\development\Krig_matlab\CEDGKrig\src\CEDGKrig\Krig.java:30: cannot access com.mathworks.toolbox.javabuilder.internal.MWComponentInstance
bad class file: C:\Program Files\MATLAB\R2010b\toolbox\javabuilder\jar\javabuilder.jar(com/mathworks/toolbox/javabuilder/internal/MWComponentInstance.class)
class file has wrong version 50.0, should be 49.0
Please remove or make sure it appears in the correct subdirectory of the classpath.
public class Krig extends MWComponentInstance<Krig>
                          ^
[total 266ms]
1 error
Error: An error occurred while shelling out to javac (error code = 1).
Unable to build executable.

I'd be grateful for a solution to this problem. Apparently I need to do more than change the JAVA_HOME variable.

Maria

Answer 1

[Kaustubha Govind]

As per the discussion on this page, it seems like the error is due to the fact that the compiled MATLAB code was built using Java 6, and Java 5 doesn't understand the format.

Perhaps you could create another version of the class file by compiling with MATLAB and JDK 1.5 and maintain it separately from the one compiled with JDK 1.6.

[Maria]

Thanks for your answer, and this is indeed what I am trying to do: I changed my JAVA_HOME to point to 1.5 so that I can compile with 1.5 and keep a separate version. But it complains that the file javabuilder.jar (in the javabuilder toolbox folder) has a different version, that is, 1.6.

So how can i change the version of the MATLAB own jar files such as javabuilder.jar? Do I need to use an older version of MATLAB? If so, which one is the last to use JAVA 1.5?

Or is there another solution?

Thanks in advance for your replies.

[Chirag Gupta]

<http://www.mathworks.com/support/compilers/R2010a/win32.html Supported Compilers (10a)>

[Kaustubha Govind]

In case it isn't clear, it seems like Chirag is suggesting use of R2010a for compiling with Java 1.5

[Maria]

Excellent, thanks, I will try this out.

[Maria]

2010a worked just as I wanted, Thanks.