Should I add both JAVA_HOME and JRE_HOME in environmental variable, PATH?

Question

I ran into this error while setting up my Tomcat and Java environmental path:

Neither the JAVA_HOME nor the JRE_HOME environmental variables is defined. At least one of the 2 environmental variables is needed to run this program.

In the user variables: I created JAVA_HOME variables and add C:\Program Files\Java\jdk1.8.0_25 to its path. and then did an edit of system variable PATH, added C:\Program Files\Java\jdk1.8.0_25; to the beginning of the its path. I also created JRE_HOME in user variable and added C:\Program Files\Java\jre1.8.0_25 to its path.

Is it necessary to create JRE_HOME and should I add the JRE path to the system variable also?

Answer 1

This answer explains all the steps with screenshots and examples

Better Use the 8.3 directory-format. In fact No spaces, ever.

1. JAVA_HOME - your JDK folder
   C:\Program Files\Java\jdk1.6.0_45 == C:\PROGRA~1\Java\JDK16~1.0_4
C:\Program Files\Java\jdk1.7.0_71 == C:\PROGRA~1\Java\JDK17~1.0_7
C:\Program Files\Java\jdk1.8.0_25 == C:\PROGRA~1\Java\JDK18~1.0_2
C:\Program Files\Java\jdk1.9.0 == C:\PROGRA~1\Java\JDK19~1.0
   

2. JRE_HOME
C:\Program Files\Java\jre6 == C:\PROGRA~1\Java\jre6
C:\Program Files\Java\jre7 == C:\PROGRA~1\Java\jre7
C:\Program Files\Java\jre1.8.0_25 == C:\PROGRA~1\Java\JRE18~1.0_2
C:\Program Files\Java\jre1.9.0 == C:\PROGRA~1\Java\JRE19~1.0
   
   

3. Addition to PATH - best practice!

   • USE WINDOWS+R
   • Enter C:\Windows\system32\systempropertiesadvanced.exe

   • Add ;C:\ProgramData\Oracle\Java\javapath; to the end of PATH
     (System Variables not User Variables).
     

   • Click OK, explore to C:\ProgramData\Oracle\Java\ and rename javapath folder (from C:\ProgramData\Oracle\Java\javapath\) to javapath_old.

   • Create new folder named javapath.
   • Start CMD and browse into (the now empty) C:\ProgramData\Oracle\Java\javapath\.

   • Run to create symbolic links:
     

     1. ln -s "C:\Program Files\Java\jre7\bin\java.exe" java.exe
        
     2. ln -s "C:\Program Files\Java\jre7\bin\javaw.exe" javaw.exe
        
     3. ln -s "C:\Program Files\Java\jre7\bin\javaws.exe" javaws.exe
        
        
   • Done with PATH and *_HOME, now let's continue with the Windows Registry.

4. Open up you preferred registry editor (Registry Workshop is the best), browse HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Development Kit notice all installed versions are shown as keys, double click CurrentVersion (REG_SZ value) and modify its data to your preferred SDK version, mine is 1.7 (For Android Studio)

5. Do the same for HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment (with CurrentVersion)

6. Close down java-based programs such as eclipse or IntelliJ,

   • Open up task-manager- processes tab,
   • Look for explorer.exe, cmd.exe and java(*something*).exe programs,
   • Right-click eache and click End Task (not "End Process-Tree"!)
   • Click File➩New Task➩enter explorer.exe
     .

The changes you've done above were applied successfully
No need to reboot, no need to log-off/on again.