miniJVM

Develop iOS Android app in java, Cross platform java virtual machine , the minimal jvm .

Features:

• Jvm Build pass: iOS / Android / mingw-w64 32|64bit / cygwin / MSVC 32|64bit / MacOS / Linux
• No dependence Library
• Minimal memory footprint
• Minimal binary, embedded jvm
• Minimal bootstrap classlib
• Support embedded java source compiler(janino compiler)
• Jit support
• Low latency java garbage collection
• Java remote debug supported, JDWP Spec
• Translate minijvm classes to C source code to improve performance.

iOS/Android Platform Extended Features:

• OpenGL ES 2.0 / 3.0
• Swing like gui lib, XML gui html like layout
• Audio Playback and Capture
• Take photo from Camera or Album
• Save and Load file from mobile storage
• Api compatible with miniJVM desktop platform, app can running on desktop platform

MiniJVM on Web:

MiniJVM on web build by Starcommander. Source MiniJVM Web demo

MiniJVM gui Demo

• Instant Message app Demo , Source
• BiBiX binary can be download from : BiBiX.jar
• 3D game app Demo, Source
• G3D binary can be download from : g3d.jar
• Mobile platform : First build and install AppManager for iOS /mobile/iosapp , Or build and install for Android /mobile/androidapp ,then download demo in AppManager and run these app
• Desktop computer: /binary/win_64 , /binary/macos , /binary/win32 , /binary/centos_x64 run test.sh

Architecture:

Changelog:

2021.03. Add j2c module, it 's a tool for convert minijvm java source code to c source code , then build it as native application , support desktop and mobile platform .
2020.12. Add build script and release v2.1.
2020.10. Refactor source and remove binary in repository.
2020.10. Https supported.
2020.03. Add xml layout for gui system, add 3D game demo for minijvm, fix jdwp debug for jetbrain idea.
2019.12. Bind cross platform awtk ui system , see awtk-minijvm
2019.12. Jit enabled, it based on sljit project
2019.10. Jit is developing
2018.12. Optimize performance
2017.09. miniJVM start

Build for iOS/Android platform:

Write java code once , running on all of iOS / Android / MacOSX / Win / Linux platforms
There were not essential jar file pre-built, so build these jar file first
Develop IDE: Eclipse, Netbeans or Jetbrain Intelli Idea

• Run script /mobile/build_jar.sh or /mobile/build_jar.bat to generted jars.
  Or

Build maven projects /minijvm/java copy to /mobile/assets/resfiles/minijvm_rt.jar
Build maven projects /mobile/java/glfm_gui, copy to /mobile/assets/resfiles/glfm_gui.jar
Build maven projects /mobile/java/ExApp, copy to /mobile/assets/resfiles/ExApp.jar
Maybe you can change /mobile/java/ExApp/src/main/java/test/MyApp.java , Add your resource to /mobile/java/ExApp/src/main/resource/res/ , such as audio or image etc, Configure /mobile/java/ExApp/src/main/config.txt for icon ,version, boot class, etc

• XCode open /mobile/iosapp ,setup developer account in Signing&Capabilities , build and install app to Device , verify app before running app (Setting->General->Device Management->{Developer account}->Verify App->Trust)
• Android Studio open /mobile/androidapp build and install app to Android device
• AppManager is running, It can start a in-app webserver for upload app, and download app from a website too
  
  

Build for Webbrowser

MiniJVM runs (restricted) directly in a Webbrowser.

• Use the scripts in miniJVM/web
• For jars use the same /binary/build_jar.sh

Screenshot Console-App

Screenshot GUI-App

Web examples:

https://java-on-web.org/examples/

Build for Windows/Linux/MacOS platform:

There were not essential jar file pre-built, so build these jar file first

• Run script /binary/build_jar.sh or /binary/build_jar.bat to generted jars
  Or

Build java bootstrap classes /minijvm/java , Maven build jar and copy to /binary/lib/minijvm_rt.jar
Build gui classes /desktop/glfw_gui/java , Maven build jar and copy to /binary/libex/glfw_gui.jar
Build console test case classes /test/minijvm_test , Maven build jar and copy to /binary/libex/minijvm_test.jar
Build gui test app classes /mobile/java/ExApp , Maven built jar and copy to /binary/{platform}/apps/ExApp.jar

• Run /binary/build_mac_linux.sh or /binary/build_wini686.bat or /binary/build_winx64.bat to generted binaries
  Or

Build gui jni c dynamic library /desktop/glfw_gui/c by cmake
Build minijvm /minijvm/c by cmake

• Run test script /binary/{platform}/test.sh | test.bat

How to Remote debug:

Desktop platform : Run mini_jvm with flag: -Xdebug for debug mode iOS/Android simulator : change /mobile/c/glfmapp/main.c , set jvm->jdp_enable = 1 after jvm_create()
iOS/Android device : check the device ip address from General Setting -> wifi ->(i)
mini_jvm jdwp listen port is 8000

• Intelli idea : open the java project , menu Run -> Edit Configurations , + remote , Transport : socket , Debugger mode : attach , host is your mini_jvm running at host ip and port ,ex "localhost:8000"
• Eclipse : configuration like as idea
• Netbeans : open java project , menu Debug -> connect to Debugger, Connector : SocketAttach , host is your mini_jvm running at the host and port, ex. "localhost:8000" , Timeout: 10000
  Then you can setup breakpoint or pause mini_jvm and watch variable's value

Project based miniJVM:

Awtk-minijvm :AWTK cross platform native ui bind to minijvm
LWJGUI-Mobile : java LWJGL UI library
BiBiX : java instantial messager
G3d : java 3d game demo
MiniJVM web demo : miniJVM on web demo

Referenced project and technology:

Oracle CLDC :referenced cldc api
OpenJDK : referenced java api
Miniz :for read jar files
Glfm :for cross platform (android/ios) GUI
Nanovg :for GUI paint function
Stb :for GUI truetype font and image
Glad :for replace openGL/GLES head file
Glfw :for pc cross platform GUI
Dirent :for linux style on win vc file and directory access
Tinycthread :for cross platform thread
JRegex :for java String regex match
Janino :for compile java source file
MiniAudio :for java audio playback and capture
Sljit :Platform independent low-level JIT compiler
Mbedtls :Https support by mbedtls
Avian :referenced java api

Development IDE usage:

C / ObjC: JetBrains CLion ,Xcode ,Virtual studio
Swift : XCode
Java : Jetbrain Idea, Netbeans
Android : Android Studio

Build GUI application, depend on OpenGL or OpenGLES

• iOS/Android system build with GLFM (/mobile/iosapp/ , /mobile/androidapp/)
• Window system build with GLFW (/desktop/glfw_gui/)
• GUI build with Nanovg
• Based on OpenGL 3.3 and OpenGLES 3.0 as default

Using miniJVM in project

Copy C source /minijvm/c to your project source folder, copy built jar minijvm_rt.jar to you projec resource folder

#include "jvm/jvm.h"

int main(int argc, char **argv) {
    char *bootclasspath = "../../binary/lib/minijvm_rt.jar";
    char *classpath = "../../binary/libex/minijvm_test.jar;./";
    char *main_name = "test.Foo3";

    s32 ret = 1;
    MiniJVM *jvm = jvm_create();
    if (jvm != NULL) {
        jvm->jdwp_enable = 0; //value 1 for java remote debug enable
        jvm->jdwp_suspend_on_start = 0;
        jvm->max_heap_size = 25 * 1024 * 1024; //

        ret = jvm_init(jvm, bootclasspath, classpath);
        if (ret) {
            printf("[ERROR]minijvm init error.\n");
        } else {
            ret = call_main(jvm, main_name, NULL);
        }
        jvm_destroy(jvm);
    }
    return ret;
}

Example of mobile gui application

The example demonstrate how develop java app for iOS and Android UI layout xml file MyForm.xml

<form name="FORM_MAIN" w="100%" h="100%">
    <script>
        <![CDATA[
        sub change()
            red=mod(random(),255)
            green=mod(random(),255)
            blue=mod(random(),255)
            setColor("LAB_HELP",red,green,blue,255)
            setText("LAB_HELP","Only a test")
        ret
        ]]>
    </script>

    <frame name="FRAME_TEST" w="80%" h="500" align="top,hcenter" title="WINDOW">
        <label name="LAB_HELP" w="100%" h="30" align="hcenter,vcenter">Help text:</label>
        <input w="100%" h="395" multiline="1" edit="0"><![CDATA[
            This app is an example of mini_jvm, Threre are a menu and a frame .
            Touch the 'Exit to AppManager' , you will enter the AppManager, AppManager manage all app, it can upload ,download , delete app.
            1. DOWNLOAD : Put your jar in a website , then input the url of jar in AppManager, Touch 'Download' ,it would download the jar ,then update the app list.
            2. UPLOAD : The first you touch the 'Start' to open the inapp webserver, then open browser in your Desktop Computer, open 'http://phone_ip_addr:8088' , and pickup a jar in the page, upload it. NOTE: That computer and the phone must be same LAN.
            3. RUN : Touch the App name in the list, Touch 'Run' can start the app.
            4. SET AS BOOT APP : The boot app will startup when MiniPack opend.
            5. UPGRADE : AppManager will download the new jar ,url that get from config.txt in jar.
            6. DELETE : The app would be deleteted.;
            ]]>
        </input>
        <br/>
        <button name="BT_SCRIPT" h="40" onclick="change()">{Change}</button>
        <button name="BT_CANCEL" h="40">{Cancel}</button>
        <br/>
    </frame>

    <menu name="MENU_MAIN" x="0" y="90%" w="100%" h="10%" fixed="1">
        <mi name="MI_OPENFRAME" pic="/res/hello.png">{Test}</mi>
        <mi name="MI_EXIT" pic="/res/appmgr.png">{Exit}</mi>
    </menu>
</form>

Java source file MyApp.java

package test;

import org.mini.apploader.AppManager;
import org.mini.apploader.GApplication;
import org.mini.gui.*;
import org.mini.layout.UITemplate;
import org.mini.layout.XContainer;
import org.mini.layout.XEventHandler;

/**
 * @author gust
 */
public class MyApp extends GApplication {

    GForm form;
    GMenu menu;
    GFrame gframe;

    @Override
    public GForm getForm() {
        if (form != null) {
            return form;
        }
        //set the default language
        GLanguage.setCurLang(GLanguage.ID_CHN);

        //load xml
        String xmlStr = GToolkit.readFileFromJarAsString("/res/MyForm.xml", "utf-8");

        UITemplate uit = new UITemplate(xmlStr);
        UITemplate.getVarMap().put("Cancel", "CANCEL"); //replace keywork in xml
        UITemplate.getVarMap().put("Change", "Change");
        UITemplate.getVarMap().put("Test", "Test");
        UITemplate.getVarMap().put("Exit", "QUIT");
        XContainer xc = (XContainer) XContainer.parseXml(uit.parse());
        int screenW = GCallBack.getInstance().getDeviceWidth();
        int screenH = GCallBack.getInstance().getDeviceHeight();

        //build gui with event handler
        xc.build(screenW, screenH, new XEventHandler() {
            @Override
            public void action(GObject gobj) {
                String name = gobj.getName();
                switch (name) {
                    case "MI_OPENFRAME":
                        if (form.findByName("FRAME_TEST") == null) {
                            form.add(gframe);
                        }
                        break;
                    case "MI_EXIT":
                        close();
                        break;
                    case "BT_CANCEL":
                        gframe.close();
                        break;
                }
            }

            public void onStateChange(GObject gobj, String cmd) {
            }
        });
        form = (GForm) xc.getGui();
        gframe = (GFrame) form.findByName("FRAME_TEST");
        if (gframe != null) gframe.align(GGraphics.HCENTER | GGraphics.VCENTER);
        menu = (GMenu) form.findByName("MENU_MAIN");

        //process Hori screen or Vert screen
        //if screen size changed ,then ui will resized relative
        form.setSizeChangeListener((width, height) -> {
            if (gframe != null && gframe.getLayout() != null) {
                form.getLayout().reSize(width, height);
                gframe.align(GGraphics.HCENTER | GGraphics.VCENTER);
            }
        });
        return form;
    }
}

Third liberies

• Janino java compiler

Project: Janino
Janino is a super-small, super-fast Java compiler.
Janino can not only compile a set of source files to a set of class files like JAVAC, but also compile a Java expression, a block, a class body, one .java file or a set of .java files in memory, load the bytecode and execute it directly in the same JVM. Janino compiler is not the full java compiler, see limitation , like :

List<String> list=new ArrayList();
list.add("abc");
String s=(String)list.get(0);//can't ignore (String) cast qualifier.

Download jars :
janino.jar
commons-compiler.jar

#compile /binary/res/BpDeepTest.java
mini_jvm -bootclasspath ../lib/minijvm_rt.jar -cp ../libex/janino.jar:../libex/commons-compiler.jar   org.codehaus.janino.Compiler  ../res/BpDeepTest.java

• Luaj

Project: Luaj
miniJVM adapted : [Luaj minijvm] https://github.com/digitalgust/minijvm_third_lib Lightweight, fast, Java-centric Lua interpreter written for JME and JSE, with string, table, package, math, io, os, debug, coroutine & luajava libraries, JSR-223 bindings, all metatags, weak tables and unique direct lua-to-java-bytecode compiling. Download jars :
luaj.jar

mini_jvm -bootclasspath ../lib/minijvm_rt.jar -cp ../libex/luaj.jar Sample

Screen shot :

• Windows mini_jvm gui

* Macos mini_jvm gui

* Linux mini_jvm gui

* Web mini_jvm gui

Directories:

/

binary/-------- minijvm binary for build(win32/win64/mac/linux/android/ios)
minijvm/

c/------------ minijvm c source
java/--------- minijvm runtime library

desktop/

glfw_gui/------ desktop computer gui/audio native module

j2c/------------ java to c translator.

app/----------- native support source.
build/--------- build files for platforms.
translator/---- tool for convert minijvm java source to c source.

mobile/

c/------------- java native lib, glfm framework, gui jni, glfmapp
java/glfm_gui-- mobile platform native gui lib
java/ExApp----- java app entry point
iosapp/-------- iOS launcher
androidapp/---- Android launcher
assets/resfiles/- mobile app resource, font files, jar files ,pic ,audio etc.

test/

jni_test/------ jni example
jvm_ios/------ ios swift test project
jvm_macos/---- macosX test project
jvm_vs/------- windows virtual studio test project
minijvm_test/-- test case of /minijvm/java

License

License: MIT

Gust , digitalgust@163.com .