After installation and adding path, JDK closes immediately

Question

I've followed the steps to adding the path name to my environmental variables, and it clearly did something because if I remove or significantly alter this path then when I type "javac" or "java" into the command prompt it simply says file cannot be found. But with the path added, a screen opens and then closes in a fraction of a second. In that flash it does look like the screen this app shows as the next step.
Why is it closing immediately and how can I keep it open? I've read other threads already.
Thank

Answer 1

Open Command Prompt (or cmd) first and then type in java or javac.