Do not change property jna.nounpack if it did have value

[AoEiuV020]

android can also run normal java application,
if always set the property true,I should do so,

        try{
            Class.forName(Platform.class.getName());
        }catch(Exception ignore){
        }
        System.setProperty("jna.nounpack","false");

https://github.com/AoEiuV020/RunJavaOnAndroid/blob/master/jna/src/main/java/aoeiuv020/Main.java
It's stupid,
if there is a check befor set in class Platform,
I should only set the property with single line,

[matthiasblaesing]

In general I agree with this change, but I'm interested in the reasoning and I don't understand your description:

"android can also run normal java application"

AFAIK this is only true, if you run a complete JRE build for the bionic C library. Dalvik can (again AFAIK) only run DEX and fails to interpret java class files. So what is it you are trying to do?

[AoEiuV020]

see my project, link have pasted ,
test it with command "./gradlew :jna:dalvikvm"
only dex right,
I mean we can run java main method on android like do on pc, without any apk file,
with command "dalvikvm", for example,
there is a xxxxxx.jar has class Hello,
class Hello has the main method,
use android build tool "dx" translate it to xxxxxx.dex, and push it into android,
we can run these commands on android,

export CLASSPATH="xxxxxx.dex"
dalvikvm Hello

just like do this on pc,

export CLASSPATH="xxxxxx.jar"
java Hello

[matthiasblaesing]

Thanks - I did not realize that, but in hindsight it is logical. Could you please adjust the change to use braces for the if-then block?

[twall]

jna.nounpack should always be true on android, since that system does not support loading of arbitrary jars or native libraries (unless something has changed recently). All jars and native libraries must be declared and explicitly included as part of your project.

…

On Mon, Apr 17, 2017 at 12:56 AM, 啊o额iu鱼 ***@***.***> wrote: android can also run normal java application, if always set the property true,I should do so, try{ Class.forName(Platform.class.getName()); }catch(Exception ignore){ } System.setProperty("jna.nounpack","false"); https://github.com/AoEiuV020/RunJavaOnAndroid/blob/master/ jna/src/main/java/aoeiuv020/Main.java It's stupid, if there is a check befor set in class Platform, I should only set the property with single line, ------------------------------ You can view, comment on, or merge this pull request online at: #792 Commit Summary - Do not change property jna.nounpack if it did have value File Changes - *M* src/com/sun/jna/Platform.java <https://github.com/java-native-access/jna/pull/792/files#diff-0> (3) Patch Links: - https://github.com/java-native-access/jna/pull/792.patch - https://github.com/java-native-access/jna/pull/792.diff — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#792>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAuMrfXUoJZF5Xj8D9saBh0PUJt5WI1oks5rwvEBgaJpZM4M-3wT> .

[AoEiuV020]

@twall no,no,no,
Have you have a look with my project?
android can run a jar file with a classes.dex and other resources in it,
I have made a project use jna ,
this project have a main method and not produce any apk file,
but it really can run on android,
and it must unpack libjnidispatch.so from jar just like on pc,

[matthiasblaesing]

@AoEiuV020 it is not nearly as simple as you make it. I build a sample application and "dexed" it. But then the dalvikvm still refuses to load the file:

1|tsubasa:/sdcard # dalvikvm -cp test-dex.jar aoeiuv020.Main
Exception in thread "main" java.lang.UnsatisfiedLinkError: dlopen failed: library "/tmp/jna-3506402/jna562335649.tmp" needed or dlopened by "/system/lib/libnativeloader.so" is not accessible for the namespace "classloader-namespace"
at java.lang.Runtime.load0(Runtime.java:908)
at java.lang.System.load(System.java:1505)
at com.sun.jna.Native.loadNativeDispatchLibraryFromClasspath(Native.java:947)
at com.sun.jna.Native.loadNativeDispatchLibrary(Native.java:922)
at com.sun.jna.Native.(Native.java:190)
at aoeiuv020.Main.main(Main.java:17)

So google seems to have decided to make it even harder to load native libraries (in fact this is documentent).

This is what I did:

mkdir test2;
cd test2;
mkdir src;
mkdir result;
cd src;
wget https://raw.githubusercontent.com/AoEiuV020/RunJavaOnAndroid/master/jna/src/main/java/aoeiuv020/Main.java;
cd ..;
cd result;
unzip ~/src/jnalib/dist/jna.jar;
cd ..;
javac -source 1.7 -target 1.7 -d result -cp result src/Main.java;
cd result/com/sun/jna;
mkdir android-arm;
cd android-arm;
unzip ~/src/jnalib/dist/android-arm.jar libjnidispatch.so;
cd ../../../../../;
jar cvf test.jar  -C result .;
/usr/lib/android-sdk/build-tools/23.0.2/dx --verbose --dex --output test-dex.jar test.jar;
adb push test-dex.jar /sdcard/test-dex.jar

[AoEiuV020]

@matthiasblaesing I don't know why,
but you can have a look android7.0 changed about ndk,
https://developer.android.com/about/versions/nougat/android-7.0-changes.html#ndk
and can you tell me your android version,jna version,
It's OK on my android7.1.2 with build tool 25.0.2, use jna 4.4,

[matthiasblaesing]

It still does not work (chaging tmp does not help)

• JNA is the master revision
• Android is lineage OS:
  • 7.1.1
  • 14.1-20170324-NIGHTLY-tsubasa

[matthiasblaesing]

I'll close this here. Android seems to lock down what can be done with regard to loading arbitrary libraries from the system. I don't see an indication the google will step back from that.

In principal I'm ok with this change, but I'd like to see it in action first. I'm willing to test this in other constallations, but my phone is the easiest (and only) option for me.