Whats the diff between j2re1.4 and jdk1.2 1

[Evan145]

Hi guys,

I just downloaded Opera web browser. During the install, it installed "j2re1.4.2-04" into C:\Program Files\Java.

My system already had "jdk1.2.2" in C:\ went I purchased it.

I am a novice with Java so I dont know if these are
two different applications or not?

Should I uninstall the jdk1.2.2 or leave it?

Also, my PATH contains C:\jdk1.2.2\bin;C:\jdk1.2.2\lib.
Should the j2re1.4.2-04 be in my PATH too.

what is CLASSPATH used for?

Evan

 

[jemminger]

the jre is just the java runtime environment. the jdk is the java development kit, used by java programmers.

if you're not programming in java, don't worry about it...you can leave the jdk installed with no problems.

classpath tells the compiler and/or jre where to find core java classes and additional classes/jars required by your application.

opera probably installed the jre to run applets...if applets don't work within opera, then perhaps add the jre to classpath, after the 1.2

if you want to program in java, i would uninstall 1.2 and get jdk1.4.2


=========================================================
-jeff

http://www.jeffemminger.com

try { succeed(); } catch(E) { tryAgain(); } finally { rtfm(); }

 

[Evan145]

Thanks jeff

So what does this mean when I type java -version at prompt.
Is the 1.4.2, the runtime environment not the dev kit 1.2?


C:\WINDOWS>java -version
java version "1.4.2_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_04-b05)
Java HotSpot(TM) Client VM (build 1.4.2_04-b05, mixed mode)

 

[sedj]

SDK - Standard Development Kit - What you need to compile java programs. JDK is the old name for SDK.

JRE - Java Runtime Environment - What you need to run java programs.

The SDK contains a JRE.

When you type "java -version" it tells you the version of the JRE - not the SDK. Now this may be picking up your JRE that comes with the SDK, or it may be picking up some other JRE.
In your specific case, if you have the J/SDK version 1.2, and a 1.4 JRE, then the default JRE is not the one with your SDK, but the 1.4 JRE (probably installed in "C:\Program Files\Java[Soft]"

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[Evan145]

Thank you for the explaination.
Im now regreting dowloading that Opera. I get java errors on pages with applets .
I think Ive done more harm than good.

I remove all references to Java in Add/Remove programs.
Then dowloaded a new SDK and now applets run.

So now my system looks like this

Control Panel/Add Remove Programs (2 Entries)
-- Java 2 Runtime Environment, SE v1.4.2_05
-- Java 2 SDK, SE v1.4.2_05


C:\WINDOWS>java -version
java version "1.4.2_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_05-b04)
Java HotSpot(TM) Client VM (build 1.4.2_05-b04, mixed mode)

In Windows Explorer i see
C:\j2sdk1.4.2
C:\Program Files\Java\j2re1.4.2_05
C:\Program Files\JavaSoft\JRE\1.2\lib\applet\WMPNS.jar (only the single jar file exists in any of these folders)

Heres a screenshot of HKEY_LOCAL_MACHINE\Software\JavaSoft

http://www.geocities.com/jlmcork/help/sshot.html

Can you tell if anything looks wrong. Or should I leave well enough alone now.

Evan

 

[sedj]

I'm not windows registry expert, but it looks OK to me ...

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