Registry Key '...' has value '1.7', but '1.6' is required. Java 1.7 is Installed and the Registry is Pointing to it

My development team recently was forced over to a remote development environment where we do not have full access to the servers. Before the change over we had a JAR that was running fine on Java 1.7 x64 along with JRE 7. When we moved over to the new server our JAR was running alright, but then one of the server admins "updated" our Java to an older version and uninstalled the one we were using. Don't ask me why, I don't know. I re-installed Java 1.7 and uninstalled 1.6 along with the JREs.

The following problem occurs at runtime, there are no build errors:

Registry key 'Software\JavaSoft\Java Runtime Environment\CurrentVersion'
has value '1.7', but '1.6' is required.
Error: could not find java.dll
Error: could not find Java SE Runtime Environment.

I've run the same JAR on my laptop with no issues. Both the server and my laptop have JDK 1.7 and JRE 7 in the respective %HOME% variables and system PATH. I've even reinstalled JRE 6 and placed it later in the system environment PATH variables with the same result.

I have also changed the registry back to look at 1.6 and it results in the following, which I looked up and it appears to be from having multiple Javas installed (leading back to my original problem):

Exception in thread "main" java.lang.UnsupportedClassVersionError: ... :
Unsupported major.minor version 51.0

I would appreciate any insight you all have as I have been looking over various forums but nothing seems to have exactly my problem. Also, this has happen on another server we are using as well. Thanks!

Update: No luck with recompiling the JAR to either 1.6 or 1.7 and matching the JDK. Also, why in the world would a newer version of Java break an older compiled version?

This happens when you somehow confused java itself. You are trying to run a java 6 VM where it found a JRE 7. It might show this problem even if you type in the command line just java or java -version in a misconfigured environment. The JAR is not the problem, except in the very unlikely case where the code in JAR is looking in the Windows Registry for that (which probably is not your case).

In my case, I had the java.exe, javaw.exe and javaws.exe from Java 6 in the Windows/System32 folder (don't know how it got to be there). The rest of the JDK and JRE where found in the PATH inside C:\Java\jdk_1.7.0\bin. Oops!

Just had the similar error when installing java 8 (jdk & jre) on a system already running Java 7.

Error: Registry key 'Software\JavaSoft\Java Runtime

Environment'\CurrentVersion' has value '1.8', but '1.7' is required.

Error: could not find java.dll Error: Could not find Java SE Runtime Environment.

My environment was set up correctly (Path & java_home correctly defined), but the problem arises from the way pre-8 Java installers worked, which is that they used to copy the three executables (java.exe, javaw.exe & javaws.exe) to the Windows system directory. These remain unless overwritten by a new pre-8 installation.

However the Java 8 installer instead creates symbolic links in a new directory, C:\ProgramData\Oracle\Java\javapath, pointing to the actual JRE 8 location.

This means that you'll actually run the old 7 exes but use the new 8 DLLs.

So, the solution is simply to delete the 3 Java exes, as above, from the windows system directory.

If you are running 32-bit Java on a 64-bit Windows, the exes would be in Windows\SysWOW64, otherwise in Windows\System32.

I've deleted java files at windows/system32 and I also have removed c:\ProgramData\Oracle\Java\javapath from the PATH variable, because there was 3 symlinks to java 1.8 files.

I had JDK 1.7 in the %JAVA_HOME% variable and java1.7/bin in the PATH.

PS1: My problem was between Java 1.7 and Java 1.8.

PS2: I can't add this as a comment to Victor's answer because I haven't enough points.

In the START menu type "regedit" to open the Registry editor

Go to "HKEY_LOCAL_MACHINE" on the left-hand side registry explorer/tree menu

Click "SOFTWARE" within the "HKEY_LOCAL_MACHINE" registries

Click "JavaSoft" within the "SOFTWARE" registries

Click "Java Runtime Environment" within the "JavaSoft" list of registries here you can see different versions of installed java

Click "Java Runtime Environment"- On right hand side you will get 4-5 rows . Please select "CurrentVersion" and right Click( select modify option) Change version to "1.7"

Now the magic has been completed