MicroEJ Java H

Principle

This MicroEJ tool is useful for creating the skeleton of a C file, to which some Java native implementation functions will later be written. This tool helps prevent misses of some #include files, and helps ensure that function signatures are correct.

Functional Description

MicroEJ Java H tool takes as input one or several Java class files (*.class) from directories and / or JAR files. It looks for Java native methods declared in these class files, and generates a skeleton(s) of the C file(s).

Dependencies

No dependency.

Installation

In SDK 6, the MicroEJ Java H tool is enabled by default. It can be disabled in the VEE Port configuration file, by adding the following property:

com.microej.runtime.extensible.MicroEJavah.enabled=false

Use

This chapter explains the MicroEJ tool options.

MicroEJ Java H Tool (SDK 6)

In SDK 6, the MicroEJ Java H tool is executed using the Gradle execTool task.

Run the following command from a project containing microejVee() dependency.

./gradlew execTool \
--name=ejavah \
--toolProperty=ejavah.natives.path="<absolute-path-to-classes>\classes;<absolute-path-to-jar>\mylib.jar"

--name=ejavah: Specifies the MicroEJ Java H tool.
ejavah.natives.path: Defines the Java classpath to scan for native methods. It can contain directories with .class files, or paths to .jar files. Entries must be separated using the system-dependent path-separator character as defined in File.pathSeparator. Usualy ; on Windows and : on Linux.

Generated .h header files are located in: build\output\include

When the execution is successful, the following type of log is displayed:

Info: com.microej.Main will not be generated as C SNI because it does not contain any native
Info: com.microej.package-info will not be generated as C SNI because it does not contain any native
Info: com_microej_NativeExample.h successfully generated in build\output