If you are sure that you have set them properly, you can print your environment variables like JAVA_HOME using any of the below methods in Windows 10.

1. Windows Command prompt ( cmd.exe )

   C:\>echo %JAVA_HOME%
   C:\Program Files\Java\jdk1.7.0_80
   

2. Git Bash within windows, you need to use the bash format

   user12231@TP-UN103 MINGW64 /c
   $ echo $JAVA_HOME
   C:\Program Files\Java\jdk1.7.0_80
   

3. From the conversation, it looks like you are using Windows 10 powershell.
   To print the environment variable in windows powershell, use one of the following commands as below

   PS C:\>Get-ChildItem Env:JAVA_HOME
   
   Name                           Value
   ----                           -----
   JAVA_HOME                      C:\Program Files\Java\jdk1.7.0_80
   

   or

   PS C:\> echo $env:JAVA_HOME
   C:\Program Files\Java\jdk1.7.0_80
   

   ---

   You can refer the Powershell documentation here.

   https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_environment_variables?view=powershell-6#displaying-environment-variables

I need help finding the location of my java_home/bin

• "Start" > "Control Panel" > "Java".

• Select "Java" tab.

  

• Click "View"

• Look in the "Path" column for version of the JRE you have installed.

  

In the above example the "Path" contains:

C:\apps\jdk\jre\bin\javaw.exe

JAVA_HOME should point to the root directory of the Java installation, so in this case:

C:\apps\jdk

And the PATH should contain JAVA_HOME\bin, in this case:

C:\apps\jdk\bin

From a command prompt we can set these values using the following commands:

setx JAVA_HOME C:\apps\jdk
setx PATH C:\apps\jdk\bin;%PATH%

Notes:

• Modify the above commands as appropriate for your Java installation.
• These are System not User environment variables.

See Installing the JDK Software and Setting JAVA_HOME and PATH and CLASSPATH for more information.

Your $JAVAHOME is pointing to the correct location. But the path should have $JAVAHOME/bin directory and not $JAVAHOME itself.

JAVA_HOME="/opt/jdk1.7.75"
export JAVA_HOME
PATH="$PATH:$JAVA_HOME/bin"

You should consider using the Oracle Java PPA instead. It usually does more than what a manual installation would do. You don't have to worry about setting up the environment variables either. That's what most people use.

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer

Try running java -version and javac -version to verify that the path is set.

On Linux you can run $(dirname $(dirname $(readlink -f $(which javac))))

On Mac you can run $(dirname $(readlink $(which javac)))/java_home

I'm not sure about windows but I imagine where javac would get you pretty close