Java version pointing to wrong version

First off I'm using Ubuntu 14.04

I was following this video to set up a Java JDK and at the end he uses

to see his current version number.

The Version I installed was 1.8.0_66 but mine returns

But when I check for the JAVA_HOME that seems to be correct

Where have I gone wrong?

Specify java version in command line

Specify java version in command line

Update java version in linux

Java 21

Java version not changing after setting java_home windows

Java version not changing after setting java_home linux

The additional resource he uses in the video is this and I feel like step 5 is maybe where things are going haywire, even though I do update the file name version before I run the script.

Any ideas? Anything is much appreciated thank you.

After digging around online I ran the line

which returned with

I've tried entering in 1 and sudo 1 etc but the java version doesn't change.

And it just redisplays the above code, without changing the default. How do I correctly enter this?

How to set default java version in redhat linux

If this is even how to do it. According to this I already had java installed in the jvm folder. Is it necessary to use the latest version of java or should I use this preinstalled version? I'm new to java so I'm not very experienced on what I need to be doing.