java - 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 FilesJavajdk1.8.0_25 to its path. and then did an edit of system variable PATH, added C:Program FilesJavajdk1.8.0_25; to the beginning of the its path. I also created JRE_HOME in user variable and added C:Program FilesJavajre1.8.0_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 FilesJavajdk1.6.0_45 == C:PROGRA~1JavaJDK16~1.0_4
C:Program FilesJavajdk1.7.0_71 == C:PROGRA~1JavaJDK17~1.0_7
C:Program FilesJavajdk1.8.0_25 == C:PROGRA~1JavaJDK18~1.0_2
C:Program FilesJavajdk1.9.0 == C:PROGRA~1JavaJDK19~1.0
   

2. JRE_HOME
C:Program FilesJavajre6 == C:PROGRA~1Javajre6
C:Program FilesJavajre7 == C:PROGRA~1Javajre7
C:Program FilesJavajre1.8.0_25 == C:PROGRA~1JavaJRE18~1.0_2
C:Program FilesJavajre1.9.0 == C:PROGRA~1JavaJRE19~1.0
   
   

3. Addition to PATH - best practice!

   • USE WINDOWS+R
   • Enter C:Windowssystem32systempropertiesadvanced.exe

   • Add ;C:ProgramDataOracleJavajavapath; to the end of PATH
     (System Variables not User Variables).
     

   • Click OK, explore to C:ProgramDataOracleJava and rename javapath folder (from C:ProgramDataOracleJavajavapath) to javapath_old.

   • Create new folder named javapath.
   • Start CMD and browse into (the now empty) C:ProgramDataOracleJavajavapath.

   • Run to create symbolic links:
     

     1. ln -s "C:Program FilesJavajre7injava.exe" java.exe
        
     2. ln -s "C:Program FilesJavajre7injavaw.exe" javaw.exe
        
     3. ln -s "C:Program FilesJavajre7injavaws.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_MACHINESOFTWAREJavaSoftJava 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_MACHINESOFTWAREJavaSoftJava 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.