Develop Reference

Version of Android studio for Mac OSX 10.7.5

I tried to install the latest version of Android studio on my OS x 10.7.5 but the AVD requires 10.8.5 or higher upto 10.9. It is not possible right now to update OSx, instead we decided to get a working version of android studio.
Which version of Android studio would work on Mac OSX 10.7.5?

There are three options from what I see here :
You install ubuntu (I recommend Linux Mint 17.2 "Rafaela" - Xfce RC (32-bit) as it's lighter on your CPU and RAM) and dual boot. You don't need to update your Mac OS 10.7.5, it will remain intact, but you will boot on linux to develop Android Apps.
There you can install the latest version of Android Studio with no hassle.
Go with the previous Android Development solution : Eclipse IDE Indigo or higher + ADT bundle plugin. Check to see what version of JDK worked on 10.7.5, install it, then install one of the versions of eclipse from Indigo to Mars and then install the above mentioned plugin.
You can try to download and run the first Android Develop Studio Beta that ever appeared on the website (0.8.0), I don't think they ever supported 10.7.5, but you can try.
My suggestion is to try to install linux (point 1) (maybe with the help of a friend), because it's important to have the latest SDK version and the latest updates.
+ It's easier to work with.

ADT failed to run on windows 7 32bit

I have a problem with running "adt-bundle-windows-x86_64-20131030" software on my laptop. I have a 32bit version of windows 7 and of course 32bit version of jre. When I want to run eclipse under that program, it fails with message:
"The version of this file is not compatible with the version of windows you're running. Check your computer's system information to see whether you need an x86 (32-bit) or x64 (64-bit) version of the program, and then contact the software publisher."
Why this is happening? (In the download page of that software it said that can be used in both 32bit and 64bit environment!).

That package name contains x86_64 which points out that this is a x64 build and not a x86 as the name could been interpreted as.
From Wikipedia:
x86-64 (also known as x64, x86_64 andAMD64) is the 64-bit version of the x86instruction set.
You can download the latest version of the adt plugin from the Android homepage:
http://developer.android.com/sdk/index.html

Here is the link for 32bit version of adt-bundle-windows 7. [http://developer.android.com/sdk/index.html]

Eclipse ADT not running on Windows XP

I downloaded the ADT Bundle from the android developers website, and I choosed the 64 bits version. When I tried running eclipse, it didn't work and I got the error eclipse.exe is not a valid Win32 application.
I am running a 64 bits Windows XP machine. I checked it by ruuning dxdiag.exe :
I don't understand why it is not working. Any idea ?

What i can see from your system information, your window xp is 32bit Operating System.
X86 represents 32-bit OS for Window XP.
Now you can do 2 things
First - Download ADT Bundle for 32-Bit.
Second - Download Eclipse Only for 32-Bit and set the path of downloaded android SDK into Eclipse.

ADT Bundle for Mac: Eclipse cannot be started

I downloaded Android Developer Tools Bundle for Mac from here. The System Requirements section says it needs "Mac OS X 10.5.8 or later (x86 only)". I tried to start Eclipse.app in adt-bundle-mac-x86_64/eclipse, but I got the following error message:
You can't open the application Eclipse.app because it is not supported
on this type of Mac.
I have a Macbook with 32-bit Intel Core Duo CPU and Mac OS X 10.6.8 and JRE 1.6.0_39. Why can't I start Eclipse from the ADT bundle? If I install Eclipse Classic 4.2.1 32-bit from here, it works.

http://developer.android.com/sdk/index.html#download
Go there and make sure you choose 32 bit for the download. That should resolve your issue.

This:
I have a Macbook with 32-bit
and this:
I tried to start Eclipse.app in adt-bundle-mac-x86_64/eclipse
do not line up. It would appear that you are trying to use a 64-bit Eclipse on a 32-bit environment, based on your description.
There does not appear to be a 32-bit OS X version of the ADT bundle, so you may need to install the SDK Tools and Eclipse separately rather than use the bundle.

which java jdk to use?

I'm on the stage of learning java, and I have the following question. On a new machine withj CPUi5, 8GB RAM and Win7 x64, which version of JDK to install? Do I install x86 or x64 version?
Also, when is about to install Eclipse, which version is recomended for my case? x86 or x64?\
After some weeks of practicing with Java, I plan to go to Adroid dev.
Many thanks!

You can choose x86 in both cases. There is no need for x64 when doing Android development.
See also Why should I use the 64-bit JDK over the 32-bit version?

If you're running a 32 bit Operating System, a 64 bit JDK or eclipse simply won't work.
If your OS is 64bit then it does not really matter, but you have to choose the same for both eclipse and the JDK because eclipse uses native libraries and you cannot mix 32 bit and 64 bit code in the same process.

I'd recommend you to install x64 bit JDK and Eclipse x64. Android is developed based on x64 JDK. This can be a reason to choose this version.
Just to remember you that you have to install only JDK 5 or JDK 6 versions. In other case you'll have problems with Android SDK.

You say you have Win7 x86, if that is really the case then you have no option and need to use a 32-bit JDK. If you have Win7 64 bit then you can use either 32 or 64 bit. In my experience it doesn't matter which one you choose as long as you install the same Eclipse version.

Your operating system is 32 bit so install 32 bit java and eclipse is not a problem for 32 bit or 64 bit.