Netbeans crashes and won't start

Question

Netbeans, javac and Java were all working fine until I installed Java 9. Now:

thufir@doge:~$ 
thufir@doge:~$ sudo update-java-alternatives --list
java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64
java-8-oracle                  1081       /usr/lib/jvm/java-8-oracle
java-9-oracle                  1091       /usr/lib/jvm/java-9-oracle
thufir@doge:~$ 
thufir@doge:~$ sudo update-alternatives --config java
There are 3 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                            Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-9-oracle/bin/java              1091      auto mode
  1            /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java   1081      manual mode
* 2            /usr/lib/jvm/java-8-oracle/jre/bin/java          1081      manual mode
  3            /usr/lib/jvm/java-9-oracle/bin/java              1091      manual mode

Press <enter> to keep the current choice[*], or type selection number: 2
thufir@doge:~$ 
thufir@doge:~$ netbeans
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.netbeans.ProxyURLStreamHandlerFactory (file:/usr/share/netbeans/platform18/lib/boot.jar) to field java.net.URL.handler
WARNING: Please consider reporting this to the maintainers of org.netbeans.ProxyURLStreamHandlerFactory
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
thufir@doge:~$ 

Why is netbeans crashing? Tried removing and re-installing the IDE. Versions:

thufir@doge:~$ 
thufir@doge:~$ apt-get -s install netbeans
NOTE: This is only a simulation!
      apt-get needs root privileges for real execution.
      Also keep in mind that locking is deactivated,
      so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree       
Reading state information... Done
netbeans is already the newest version (8.1+dfsg2-3).
The following packages were automatically installed and are no longer required:
  libkf5gpgmepp-pthread5 libkf5qgpgme5 libmimetic0
Use 'apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 699 not upgraded.
thufir@doge:~$ 
thufir@doge:~$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04 LTS"
thufir@doge:~$ 

I was using umake to handle netbeans; now trying from apt. Would like to use Java 9.

Solution

Netbeans thinks it's supposed to use java 8.1 still you just need to reinstall it so it can see the correct java version

Comments

[Tachyons]

use sudo, sudo apt-get install netbeans

[Alexey Ce]

it's already installed, that's just to show the version number: 8.1.

[Alexey Ce]

used apt to remove netbeans and re-install; same error. I think it's something like that. some sort of mismatch?

[DanNightmare]

try using apt-get purge netbeans as remove only removes binaries pretty much, and not the configuration files

[Alexey Ce]

yes, purged and then re-installed with same result.

[DanNightmare]

If you're sure it uninstalled everything, than my solution wont work. What I would still try is apt-get install aptitude which is like apt-get but smarter for all I understand, and use it to purge aptitude purge netbeans. I'm not too sure about it fixing it though

[DanNightmare]

so I've just installed netbeans myself, through apt-get, and it is netbeans 8.1, not 9. that is the problem. 9 is the one that supports Java 9. but I don't find an installation for netbeans 9, although it was supposed to be released end of july 2017

[Alexey Ce]

huh. mystery deepens. I'll take a further look into version numbers. preferably woul use umake for all this. thx for diligence.