Develop Reference

How to run Java app in Android

Is it possible to run java app (jar) in my android application? Because I need to create PDF, the problem is if I generate PDF in android, only can show with small image, if it contains large image in many pages, it will be error. So I think, I can generate PDF in java and then included to android app.

Concernig the mentiones app JBED:
Well honestly, I could not find any credible source for this tools JBED, so I would really be very cautious (e.g. who is the developer?)
In the manifestfile (in Androidmanifest.xml, where every app has to state what rights it needs to run, see How to view AndroidManifest.xml from APK file?) there are many rights mentioned (what could be necessary, as the app wants to run as an emulator), so a java application might want to send an SMS, record audio, take pictures and place calls -- so the emulator would need those rights as well.
But then the app also registers the "android.intent.action.BOOT_COMPLETED" event (i.e. autostart after boot) and this would go against every description of the tool.
Ah yeah and giveaway: The apk has a folder "certs" that has some (root-)certificates. But those are not the real certificates of the authorities, e.g. Versign. If one installs the app and by that those certificates the trust you might have in https-connections is lost because those who made the fake certificates can create own, false certificates that your phone would trust.
I assume (or am pretty sure) this is a spy tool, but I could be wrong. The (rare) testimonials that claim the tool ran perfectly will probably be the same person that posted the tool under a different name.
Andreas

You can import java Third-party libraries into Android app, follow the steps here.
I am not sure whether it will work,but just try.

If your program is a console program, the answer is yes.
Install Jvdroid from Google play. Click terminal and then write this command: java -jar YourJarFileName.jar

The simplest way would be to some install terminal emulator and then install java and then you can run java apps on standard java. You can even install full Linux distro with x server without rooting the phone, then connect to it from x client and you have Linux desktop on android. Once I've even installed eclipse for java development on it and everything worked. I tested this setup last time in 2014, but I'm pretty sure you can do this nowadays as well. The app with Linux I get from play store as well app for the x client. The app I used back then was "Debian no ROOT" or smthg like this. You need to check what's currently available to make this setup in Google Play store according to your android version and your preferences. Last time I've checked there was a lot of different tools for this kind of task. Lastly I've even successfully installed TF and keras on my android phone using terminal emulator.

You can use JBED. JBED is an .apk Android application which run java games and app on your android Device. JBED is a java android emulator, by using
this application we can install .JAR/.JAD/Java/J2ME/MIDP app on android phones.

You can do it quite easily as there are many ways to run java apps on android. Specific application called Java Emulators can do it quite easily.
These are four most popular java emulators for android viz, JBED, PhoneME, Jblend and NetMite. These are arranged in order of their preference. You can use phoneme for non rooted device, however if your device is rooted try any of the remaining three applications.

stuck in running android application in AVD

So I downloaded the ADT bundle at the android website. I tried making a simple project, the one with HelloWord program. I already added an AVD and tried to run my application. At first, I got stuck at
"Waiting for HOME ('android :process:acore') to be launched"
but after searching the net, I learned that I must right click my project and click run as Android Application and then it was able to proceed with the next lnes in the console.
But after some lines, it gets stuck at the line in the console saying
"Starting activity.com.example.myfirstapp.MainActivity on device emulator:5554"
it's been an hour since that line and nothing has happened in the AVD. I tried using 2 ADT bundles, one for my 32-bit computer and one for my 64-bit computer. Both get stuck at the same line. How do I solve this? I've been working with this issue the whole day. Just when I thought it would be a simple installation.

Launch your emulator from Android Virtual Device(AVD) Manager and run your application

One thing that can really stick your program is a virtual device that is eating up too many resources. Try lowering the amount of RAM your virtual device has. Also be sure you have the latest JDK/JRE installed.
Just picked this book up:
http://www.amazon.com/Android-Development-From-Eclipse-ebook/dp/B00EEI5NHO/
Decently well written an very easy to follow. Walks through building an app in decent detail.

Actually the AVD works very slow on normal configuration systems, it requires a very high config PC to run smooth, you have to wait for sometime to continue with AVD, it will start don't worry. But I would recommend you to run and test your apps on a real android device using the USB debugging feature.

Java Application on Smartphone

What alteration should be made in a Java Application to be able to install it on Java Enabled Smartphone?
I tried using a random app of mine to see what happens, when I open it on the cell, it says Install? I say yes, and it says invalid file.
Now I was wondering what alteration should be made?
My smartphone (Samsung S8500) runs on bada which is more or less the same as Android, but alterations in the General.

You need different SDK for smartphones. Like for Android, you need Android SDK 1.5 or any other version. You just cannot install the same application. You need to develop using the resources provided by the SDK.
If your application is Java based mobile application then you can use some tools to convert it for Android. Doesn't work every time but worth a try.
In your case, Bada OS is not like Android what i learn from here. So, you need to develop the application using J2ME .

Is it possible to develop for Android on Android?

Lately I've been doing a lot of web development on my Droid via ssh using the ConnectBot app and a few other apps for reference. I've also been doing a lot of Android development back home in eclipse, and I wondered: would it be possible to develop and test my android projects right on my phone? All I can do at the moment is either write the code via ssh and then open it later with eclipse to finish it up, or remotely use eclipse via LogMeIn Ignition or VNC. Does anyone know a native way to do what I'm trying to do, preferably offline?

Try AIDE. I use it because it supports Eclipse projects. https://play.google.com/store/apps/details?id=com.aide.ui

Not sure if this hits the target you're looking for, but The Scripting Layer for Android (formerly known as the Android Scripting Environment) is available and has a lot of power available to it.
Scripting Layer for Android (SL4A,
formerly known as Android Scripting
Environment or ASE) brings scripting
languages to Android by allowing you
to edit and execute scripts and
interactive interpreters directly on
the Android device. These scripts have
access to many of the APIs available
to full-fledged Android applications,
but with a greatly simplified
interface that makes it easy to get
things done.
Scripts can be run interactively in a
terminal, in the background, or via
Locale. Python, Perl, JRuby, Lua,
BeanShell, JavaScript, Tcl, and shell
are currently supported, and we're
planning to add more. See the SL4A
Video Help playlist on YouTube for
various demonstrations of SL4A's
features.

I found DroidScript. It's a quite powerful JavaScript interpreter thats based on the Rhino-library. It can import every Java-package and even create activities for starting from the launcher. The URL is http://droidscript.se for the Live-Editor with which you can edit scripts online and send them to your phone, and the droidscript-app has an editor, too but it cant save at the moment, i think. DroidScript is Open-Source and embeddable in an own app, I think. More info on news of DroidScript are found on droidscript.blogspot.com.

check out JAVAIDEDROID on the market

You can if you have a remote linux machine that you normaly develop on.
ssh into the machine with some ssh app.
edit the code with some console text editor (vim for example).
build the application with ant
copy the generated apk into the android phone and install it
repeat from point 2.
Good luck!

I really don't know if it's possible, but to do it, you should:
"Install" java inside Android.
"Install" ant
run ant debug
Check this link for more instructions.
PS: Please let us know if you could do it :)

J2me implementation for linux or other

I'm searching for information on how to create a j2me implementation. My target is a generic linux host... does it exist already? I mean a way to run j2me applications on linux without an emulator? Do you know where to find info?

Have a look at the phoneME project. It's not officially supported but it does run under Linux.

why do you want to do this?
the only reason I ask is j2me applications are designed for mobile devices. This means that you wont be able to run j2me applications on a standard computer without an emulator of somekind?!?
when making j2me apps in linux, the netbeans emulator has had everything I've ever needed

This looks like it might be made to do what you want:
http://www.microemu.org/
It's open source, so you can take it, tweak it, and make it run where you want.