Develop Reference

No JREs found in C:\\Program Files\java in Eclipse Scala IDE

JDK 1.8 is already installed in Windows 10 64 bit system. I am trying to create a scala project in Eclipse Scala IDE. Is says "Unbound classpath container: JRE System Library [JavaSE-1.8] in project.
While checking the Java build path-- Libraries-- JRE is coming outbound.
When I click to add JRE library, it has workspace default JRE (unbound)
While searching through preferences-- installed JRE--search. It gives no JREs.
If I try to add -- standard vm--directory ( JDK dir home). Ideally it should populate or detect all the jars but it doesn't detect.

I Tried running the application as 'Administrator' and it ran successfully.

Select your project and right click--> Build Path --> Configure Build Path -->Select Libraries--> Add Library-->JRE System Library--> Add the installed JRE here.
And if the JRE library is not getting selected, check the environment variables- JAVA_HOME and Path.
And to see if the java is correctly installed, try hitting this from CMD
java -version

Can't download JDK 8

I'm trying to setup Unity to build for Android. But I can't get the Java Development Kit. Can't download it and can't find it either.
In this answer, the guy says
To ensure JDK is installed, just go through the following :
press Win + R
type 'cmd' in the popup and press button OK.
in the console which has opened, type javac -version and press enter.
You should see as an output :
javac 1.8.0_XX
If so SDK is installed.
I did that and I got "javac 1.8.0_XX", and so I assumed I had the JDK, so I went to Unity > External Tools > JDK and tried linking the following path: "C:\Program Files\Java\jre1.8.0", and got the error message: "The path you specified does not look like a valid JDK installation. Android development requires at least JDK(1.7), having JRE only is not enough. Please make sure you are selecting a suitable JDK home directory or download and install the latest JDK: link"
I clicked the download link for windows x64 and it never loads and eventually says there's no connection. I tried the x86 as well.
In this SO question How do I find where JDK is installed on my windows machine?
Answer: For windows, in the command prompt:
c:\> for %i in (java.exe) do #echo. %~$PATH:i
And so I did that and got the path "C:\ProgramData\Oracle\Java\javapath\java.exe"
When I try linking via Unity > External tools > JDK it doesn't find any files.
I'm a bit clueless now.

#RealAnyOne, you have installed Java with JRE only installation i.e., without out a JDK that’s what you see only one folder and this is why it also showing version in the command line since it won’t check for JDK. JRE is Java Runtime Environment, JDK is Java Development Kit which contains many essential libraries. So Ideally there should be two folders JRE and JDK. This is the reason you are getting this issue with Unity.
To Fix::
Uninstall old Java 8
Download Java 8 from the oracle website
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
Install it. Now you should have two folders. Then point your Unity to it.

installing JDK and it shows empty icon

When I tried to install the JDK, it was installed but in start->java Development Kit: I faced with "empty"word.
But when I went to cmd and writed javac version or java version I saw true results and when I tried to install SDK for programming android with eclipse or install android studio I had not any problem for installing
But after installing when I created a new project in both softwares I had problems.
What I must do? Every time I try to install JDK it is installed as now.

I can't get Eclipse Luna to run on my mac

I have a mac running os x 10.9.4 and I downloaded the newest version of eclipse. It downloaded fine and installed but whenever I try to open it, I get an error that says, "Version 1.6.0_65 of the JVM is not suitable for this product." I downloaded and installed Java 7 and tried opening eclipse again only to get the same error. Anybody know how to fix this? Thanks

Make sure you have the JDK installed. Google will point you to the runtime engine (JRE) if you search for a Java download (probably called jre-7u67-macosx-x64). Click on "show all Java downloads" in the download page and look for a link "looking for the JDK?" on the left . As of today, the JDK can be found here and should have a name like jdk-7u67-macosx-x64 or jdk-8u20-macosx-x64. Both should be fine for a recent Eclipse Luna install.
If you want to run Eclipse Luna with Java 1.6, you can change the entry in the .ini file. Open the Eclipse application bundle by control-clicking and select "show contents". You will open a new finder window with a single folder "Contents". Open it, then open the folder "MacOS" and edit the file eclipse.ini which you will find inside. Change the line -Dosgi.requiredJavaVersion=1.7 to -Dosgi.requiredJavaVersion=1.6. Close and save, and now Eclipse will run in a minimum configuration. But you really want to install the 1.7 JDK.

For those using Mac OS X Mountain Lion (10.8)+. When you launch Eclipse for the first time, you may see the message "Eclipse can't be opened because it is from an unidentified developer."
To launch Eclipse for the first time, press the control key, click on the Eclipse icon, and select Open.

How does Eclipse-ADT find JDK Path

I am working with the Eclipse ADT+ADK bundle, adt-bundle-windows-x86-20131030 on Win 8. I also installed Java JDK 1.6 and i see it was installed in
C:\Program Files (x86)\Java\jdk1.6.0
Android ADT is working fine for me (it compiled few projects i tried - hello world and I was able to run this app on device as well)
I know the Eclipse-ADT uses JAVA_HOME variable to locate the JDK, but strangely when I checked my Windows 8 environment Variables there is no JAVA_HOME variable, which puzzled me.
How is Eclipse-ADT getting JDK path?
Also is there any other preference/setting which tells Eclipse ADT about Java ADK path?
Note: I have another JDK 1.7 installed at C:\Program Files\Java\jdk1.7.45

For Android SDK PATH, you can modify SDK location in subpage Android of dialog 'Preferences' (open it from menu "Window-Preferences").
For JDK, it's fine if javac can be found from environment variable PATH.