NoClassDefFoundError on external library project for Android - java

I use eclipse for Google Android development.
I've created a library project ([x] Is Library in the Android-settings), which includes an external jar-file (Referenced Libraries). This library project are referenced in another Project (the actual project which will use the library project). This is done by add the project under the Android-settings.
the source compiles but if I want to execute it on the device, I get the NoClassDefFoundError for a class which is inside the jar-file which is included in the library project.
Edit: The jar-file ist added to the exported entries ([x] my.jar on the Order and Export-Tab from the library project)
Is there a clean way to get this working?

It has been clearly stated in offcial API here:
A library project can include a JAR library
You can develop a library project that itself includes a JAR library, however you need to manually edit the dependent application project's build path and add a path to the JAR file
The jar lib must be manually added to the dependent application project's build path, not only the library project build path itself.
Update from SDK r17:
This is automatically handled by ADT now, check out new feature for ADT 17.0.0 release here:
Added feature to automatically setup JAR dependencies. Any .jar files in the /libs folder are added to the build configuration (similar to how the Ant build system works). Also, .jar files needed by library projects are also automatically added to projects that depend on those library projects. (more info)

For those who followed the steps(even check the projects in "Order and Export") and still have the java.lang.ClassNotFoundException in the API 17, the final step is to check that your compiler does not run with Java 1.7. If is 1.7 then you should change it to 1.6 for all your projects. After that it will ask to rebuild all the projects and successfully ran on my phone :)
To change the java compile version in eclipse, this is located in: Project properties > Java Compiler > Compiler Compliance level: 1.6

Go to project properties -> build path-> libraies
If you see your jar files like this
snmp4j.jar - e:\software\jars
Its may your problem
Add libs folder in your project and copy jar file in that folder. Right click jar file and go build path -> add to build path. Then you can see your jar as
snmp4j.jar - project_name/libs
Its worked for me.

I had two projects using the same library: one working, the other one crashing with java.lang.NoClassDefFoundError.
After nothing else helped me, I looked into the file project.properties in the root directory of my project.
The working project had the android.library.reference line (the last line below), the crashing one did not:
# Project target.
target=android-17
android.library.reference.1=../my-library-project
I manually added the line and it started working!
(Yes, I did try both (project) properties -- java build path -- projects and (project) properties -- java build path -- order and exports -- nothing helped.)
PS By the way, "project properties" has also the "project references" tab. No idea if it would work.

I had a minor issue when I upgraded to ADT17 where my libs weren't being imported properly. Turns out this is because my librarys were being linked as dependancies from my lib folder not libs!
Seems librarys have to be in the libs folder from now

I had a similar problem and non of the solutions out here fixed it.
Short version: the JAR was compiled in Java 1.7 and could not be found by Dalvik.
We build an internal JAR that we share across backend and mobile clients with Maven. The problem ended up being that the JAR was compiled with Java 1.7. Androids dalvik only supports Java 1.5 and 1.6. This is why everything works fine in Eclipse as it's not compiled to dalvik at this point.
We even specified the target and source version in the Maven compiler plugin to compile with Java 1.6. This did not work because only JDK 1.7 was installed on the build machine. A small note at the bottom of the Maven page gave us the hint: Note: Merely setting the target option does not guarantee that your code actually runs on a JRE with the specified version.
To see if you have this problem as well, rename your *.jar file to *.zip unpack it, and look in the MANIFEST.MF file for the Build-Jdk: parameter to see what Java version actually compiled your JAR.

Another thing to pay attention to is library package names.
If you are using ADT21 and you happen to have libraries that have the same package name, there will be error during compile but it will still compile and run in Eclipse, giving you an APK that is missing some of the resource classes. Hence the crash when you run the app.
If you compile it with ANT then you can see the compile error that says two or more libraries use the same package name.
To fix this, rename your library project by using Android Tools -> Rename Application Package. Then everything will go back to normal.
It took me almost entire day to figure this out...

Related

How to compile a Java library

I have a .jar library and used 7-zip to extract the files and edit the .java source code inside.
I need to be able to build this to update the .class files before I turn it back into a .jar.
The library won't build as it's missing dependencies, but I don't know how to add these.
The library's using JNI, and LibGDX, and as an amateur, I am out of my depth on this problem that I am stuck on.
The original .jar file is in the link below
https://github.com/finnstr/gdx-liquidfun-extension/blob/master/libs/gdx-liquidfun.jar
Download following 2 JARs and add them to the build path of your Eclipse project. If you're not using Eclipse then add them to classpath, however it will be a lot easier to do with Eclipse.
http://mvnrepository.com/artifact/com.badlogicgames.gdx/gdx/1.5.2
http://mvnrepository.com/artifact/com.badlogicgames.gdx/gdx-jnigen/1.5.2
I have included older version from 2014, as the source code that in the git for liquidfun is using some older version of classes which are not available in new version of above JARs.
Eclipse has an option to export project as a JAR file. Use that and you're done.
If you're using plain Java then you'll have to compile all directories one by one (Java: How can I compile an entire directory structure of code ?)

Update External Jar in Android Project

All, I have an external JAR that I'm adding to my Android project. However, as my jar is consistently updating and changing. When I update my JAR, I get the dalvik VM magic number error.
I don't understand how I'm supposed to fix this?
Here's the steps I've followed.
Adding The Jar Initially
Copy JAR to libs folder in my project
Run project
My JAR is picked up, installed everyone is happy.
Updating the Jar
In Eclipse, go to the jar in libs and right click -> delete.
Copy my new jar (same name) into the libs folder.
Receive bad class file magic error.
My Troubleshooting So Far
In eclipse, Project -> Clean...
Select my project, clean it.
Run it. Same error... magic number
Project Properties -> Java Build Path -> Remove Android Private Libraries
Now the private libraries aren't being re-added. (Which equates to missing imports in my Java project) Why is this a nightmare? Any suggestions?
Turns out that my issue was caused by the multiple JDK's I had. Android was defaulting to use JDK 1.7 while my console jar was using JDK 1.8

netbeans dependant libs do not compile after change

Using NetBeans 7.3 and writing Java code.
I've got a Web Server Project that is dependent on a lib (both are my code).
I've added the lib to the Server dependencies list by following the path: project properties -> libraries (add jar/folder).
If I change the code in the lib and "clean and build" the web server - the lib doesn't recompile (although NetBeans recognizes the change and alerts me with hint on problems).
I've tried with and without "compile on save" in both projects.
I am almost sure this used to work and am guessing that I probably changed something in the project to make the dependent lib not compile.
Any ideas what to look for? which parameter controls this behavior?
Well it seems all I needed to do was to add my libs as Project (project properties, Libraries, Add Project)and not as jar files...
that fixed all the dependencies issues...

Runtime Directory in Android Project

I have a android project with a runtime directory, and there is a jar file in this directory. This project can be built in eclipse. However, if I put the jar file in some other place, say, libs directory. This project would fail to build. In addition, even if I place the jar file in the runtime directory, this project cannot be built in Intellij. When the project fails to build, the error logs looks like the following.
Android Dex: [GameDemo] EXCEPTION FROM SIMULATION:
..... bad range 5..6; actual size 5
at bytecode offset 0000005
while processing ()V
So here are my questions:
Given a project in Eclipse, why project can be built when the jar file is in runtime library, but not when it's in libs directory.
Even though the jar is in runtime directory, why this project cannot be built in Itellij. What's the difference in build process of the two ide in term of android project.
Thanks!
I believe you are having this issue because you are trying to integrate CMCC's mobile SDK. It's a piece of garbage but that's another topic. For your purpose, just setting the library as "Provided" instead of "Compile" in the module settings of your IntelliJ project will get you past the compile stage. the SDK's probably loading it on the fly but not sure why that's necessary. Also be careful how you add the dynamic lib they provided. Make sure you do a plain copy instead of through the android NDK module dependency crap.
Seems they wanna avoid their sdk to be easily decompiled and byte hacked.
So they provided a dev time lib written in java that has interface feature only and implemented the real logic/type/class in a native lib.

Scala eclipse-plugin Project unmanaged dependencies of referenced projects not on classpath after upgrade from 2.9 to 2.10

I recently tried to upgrade from Scala 2.9 to 2.10 and ran into the following difficulties:
I have two scala eclipse-plugin projects. The first one has some unmanaged libraries on it's build path. This project compiles and runs fine.
The second project depends upon the first project and some Java project configured via eclipse-plugin dependencies.
Here I get four not very helpful compile errors. Three times the following
SBT builder crashed while compiling. The error message is 'bad symbolic reference. A signature in XSBInterRunner.class refers to term interprolog in value com.declarativa which is not available. It may be completely missing from the current classpath, or the version on the classpath might be incompatible with the version used when compiling XSBInterRunner.class.'. Check Error Log for details. de.wwu.sdpn.wala Unknown Scala Problem
Plus another dumping the class path which actually does not contain the corresponding library.
If I manually add the missing libraries to the second project the first project isn't found anymore. Even though it was on the dumped class path previously.
When compiling the projects from the command line via SBT using a more or less equivalent setup everything works fine.
I've also tried to reconfigure the dependencies not to use the eclipse-plugin mechanism for dependency management but directly added the other project to the build path but this also didn't help. Reimporting the projects to a clean workspace also didn't help.
The problem exists both with the 3.0.1 and the nightly version of the scala-ide plugin on Eclipse 4.2 and 4.3.
Any idea how to resolve this issue? Is there any way to find out why the libraries are missing from the class path?
From the description, it looks like the unmanaged library is not exported from the first project. Verify that in project properties > Java Build Path > Order and Export, the checkbox next to the library is selected. It is needed to make jars visible to other projects.

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