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I used to have JRE 7 before, and now I installed JDK 8 and deleted my JRE 7 folder. I'm using Eclipse Kepler, and I added JDK 1.8 to my installed JRE's. Can I delete the JRE 1.8 folder as it's taking up space in my computer? Will it cause any problems?

0xCursor
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Chris Daniel
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    You mean delete the jre folder inside of the JDK? I wouldn't do that. If it is a JRE you installed separately, then sure, kill it. – Thilo Oct 07 '15 at 09:38
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    I wouldn't delete the folder in any case and use proper uninstall procedures. – Gimby Oct 07 '15 at 11:55
  • If you don't install JRE, you can't find `java control panel` in windows and `javaws.exe` – Voyager Apr 21 '19 at 10:26

3 Answers3

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JRE is a part of JDK.

No need to have JRE when you have JDK. If you open JDK folder and see, you'll have JRE folder inside it which is the same of JRE folder initially you have.

Suresh Atta
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22

As all have said that JDK includes JRE, that is perfectly right.

But let me add more on it to fulfill an industrial Structure.

While an employee works on some project, they need JDK for they need to write code as well as compile it. But after the development process completes, the software is ready to deliver and the client's machine will have to choose whether JDK is needed or the JRE.

I would recommend to install JRE on clients' machines because clients don't have to compile the code. Clients always goes straight forward to execute it.

So, make sure to install JRE on clients' machines, not JDK. It will give the advantage of Memory - Utilization too.

Thanks.

TecHunter
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Vishal Gajera
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    Some applications do need the JDK at runtime, too, though. For example to compile JSP. Also "Memory utilization": Really? The same code run on JDK vs JRE uses different amounts of memory? – Thilo Oct 08 '15 at 00:00
  • @Thilo I mean on "Memory Utilization" i.e. use of JDK vs JRE uses different amount of Memory which affect on performance. – Vishal Gajera Oct 08 '15 at 07:55
  • @Thilo yes in terms of size, while software needs support to execute at run-time. – Vishal Gajera Oct 08 '15 at 08:41
  • I somewhat doubt that. The same application should use the same amount of memory when running with JDK or JRE. Isn't the Java runtime identical (and the JDK just has extra tools for developers)? – Thilo Oct 08 '15 at 09:07
  • @Thilo application takes same amount of memory-size for execution , whether environment is either JDK or JRE is corrent. I am only talking about JDK takes more memory compare to JRE. have you still any doubt ? – Vishal Gajera Oct 08 '15 at 09:12
  • Yes. What do you mean "JDK takes more memory compared to JRE"? Do you mean "javac" or "wsdl2java" ? That is not even part of JRE, so how can you compare? And why would the client run them anyway? Or "java" ? That should be exactly the same. The way you phrase it in your answer makes it sound like the application will perform worse if you install the full JDK. I object to that. – Thilo Oct 08 '15 at 09:17
  • Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/91737/discussion-between-mr-vishal-j-gajera-and-thilo). – Vishal Gajera Oct 08 '15 at 11:18
  • You just got to the point! – Gadrawin Jun 21 '23 at 03:09
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You can delete JRE. JDK is a superset of JRE and contains everything already.

Matthias J. Sax
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