How to remove openjdk

[Ric Moore]

On 12/14/2012 09:46 PM, Jim Byrnes wrote:
> On 12/14/2012 01:52 PM, Ric Moore wrote:
>> On 12/14/2012 10:43 AM, Jim Byrnes wrote:
>>> On 12/14/2012 02:41 AM, Ric Moore wrote:
>>>> On 12/13/2012 07:54 PM, Jim Byrnes wrote:
>>>>> I goofed. I installed jEdit on my new install of 12.04 before I
>>>>> installed Oracle's java.  jEdit pulled in openjdk which I don't want.
>>>>>
>>>>> What is the proper way to completely remove jEdit and openjdk so I can
>>>>> install Oracle's java and then jEdit just like I had never messed
>>>>> up in
>>>>> the first place?
>>>> I use this ... works a charm.
>>>> http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html
>>>>
>>>>
>>>>
>>>>
>>>> Enjoy, Ric
>>>>
>>>>
>>>
>>> Thanks,  Jim
>> It also corrects the alternative links, and adds some you may never
>> heard of. It's pretty thorough. But, I install alternatives-gtk to check
>> each and every link. Amazing just how many links there are in the
>> alternative scheme. You'll enjoy the trip. Ric
>>
>
> Maybe if I knew what the trip was about.  I'll admit my ignorance here,
> what are the "alternatives" you are referencing?


Ah... prepared to become enlightened! Within the /usr/lib/jvm scheme of 
things related to java, there are a bunch of bin/ directories. But, you 
path is usually confined to the standard /usr/bin /usr/local/bin 
directories. Plus, when you upgrade your java package the directory that 
those bin files are kept in, change with version number as part of the 
directory name. SO!! You have the "alternatives" scheme to handle all of 
those useful binary files that aren't in your usual path.

In /etc/alternatives you'll see a BUNCH of linked files, if you do an ls -la

You have the java command javac living in /usr/lib/jvm/jdk(+version)/bin
Alternatives will make a link between there to /usr/bin so that javac 
can now be readily accessed. Alternatives can become screwed up in major 
fashion when you do something like switch between OpenJDK and 
OracleJava-JDK. Stuff can potentially be linked all over the damn places 
without some sort of intervention. That link I gave you, as part of it's 
script, with make all your Oracle Java links correctly for you.

So, that is why I recommend you check the links yourself, just to be 
sure ...using alternatives-GTK, which is a nice little gui to admin your 
alternatives settings. I usually find at least one mistake, although the 
last time I found none. Best to be sure, while learning how your system 
works. Alternatives also gets edited when you chose Firefox over Chrome 
as your default browser, and other personal system choices, like editor 
and email reader, and such.

So, to conclude our lesson, check this out:

ric at iam:/usr/bin$ ls -la java
lrwxrwxrwx 1 root root 22 Dec  6 03:15 java -> /etc/alternatives/java
ric at iam:/etc/alternatives$ ls -la java
lrwxrwxrwx 1 root root 39 Dec  6 03:15 java -> 
/usr/lib/jvm/java-7-oracle/jre/bin/java

See? Install scripts can make changes in /etc/alternatives and then the 
change becomes available in /usr/bin using the same link there while the 
original target binary lives in a dynamic directory name structure.

I hope I made it clearer to you. :) Ric




-- 
My father, Victor Moore (Vic) used to say:
"There are two Great Sins in the world...
..the Sin of Ignorance, and the Sin of Stupidity.
Only the former may be overcome." R.I.P. Dad.
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