This demo allows you to run your own java code on Mavos. You require Microsoft Visual Studio 6 or higher or a similar C compiler, and you must have a java compiler such as the one provided with the Java 2 Platform Standard Edition (J2SE) from Sun Microsystems.

Download demo2

Instructions

Step 1. Write your own java class "test.Test". The system will attempt to locate the method "void main(String[])" in this class as the entry point. You may include as many classes as you wish, although the bootloader will load up to a limit of 384 kb of data, so the final disk image must be under that size. A typical disk image size is around 230 kb.

Step 2. Use your java compiler to compile your code. Note that the java code must be CLDC J2ME compliant, which means that if you use any of the J2SE API not present in J2ME CLDC and not supported by the system then an error will be thrown.

Step 3. Use the encode utility to generate a source code file that will be included with the Visual Studio project. The command line is:

encode.exe listing.txt outputFile.c [-classpath dir1;dir2;...]

The file listing.txt must contain a listing of all the java class files you wish to include, which will be the file test/Test.class and any additional files you have compiled (which must include compiler generated class files for inner classes). You may specify a classpath to help the utility locate your files, otherwise it will search from the current directory. There is an example of listing.txt provided, one that can be used with the java source from Demo 1. Note that the utility will search for the class based on its package name (as is the usual case with Java), so the "test.Test" class file must be situated in a directory named "test".

Step 4. Open the Visual Studio workspace demo.dsw. Your C source file must replace the file unlinkedStaticClassFiles.c in the Visual Studio project. Select the file unlinkedStaticClassFiles.c in the workspace window and hit the delete key, and add your source file with the "Add to Project" menu listing under the "Project" menu option. Or simply replace the text in the unlinkedStaticClassFiles.c file with the text in your source file. The file unlinkedStaticClassFiles.c is a source file produced from the java code used in the above demonstration and can be used as a reference.

Step 5. Build the project to produce a Windows executable demo.exe using the Build menu option. The build process will compile your C source file into an object source file and link with the files psEntry.obj and lib.lib.

The project options are set to link an executable with a 0x0 base address. However, this linker always relocates the code 0x1000 bytes above the specified based address, putting the code at 0x1000. The bootloader takes this address into account by loading the code at address 0x1000 instead of 0x0. Ignore any warnings that the base value of 0x0 is invalid for a Windows executable.

Step 6. Run the ExeToBin utility on the generated executable to generate a new operating system binary image. The command line is:

ExeToBin.exe demo.exe demo2.bin

Step 7. Complete all 3 steps of demo 1 with your new binary system image demo2.bin and the bootloader binary image psBoot.bin.

The system will load itself, jump into your java code and begin executing.

Notes:

•The system is configured with the following options: growable java thread stacks, a heap size of 1 MB, and garbage collection that will run when all of your threads go idle.

•The file psEntry.obj must be included as the first file in the list of files to be linked with, so that this object source file appears first in the resulting executable.