How to resolve unmet dependencies? Cannot install or remove packages

Question

$sudo apt-get -f install google-chrome-stable

I tried to install java in ubuntu but it's not successfully installed, but after that when I am trying to install/remove any other packages, I'm getting these errors:

Reading package lists... Done  
Building dependency tree  
Reading state information... Done  
You might want to run 'apt-get -f install' to correct these:  

The following packages have unmet dependencies:

    bleachbit : Depends: menu but it is not going to be installed

    ca-certificates-java : Depends: openjdk-6-jre-headless (>= 6b16-1.6.1-2) or
                                    java6-runtime-headless

    icedtea-6-plugin : Depends: openjdk-6-jre

    icedtea-netx : Depends: openjdk-6-jre (>= 6b23~pre10~) or
                            openjdk-7-jre

**E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).**

When i run the sudo dpkg --configure -a to get the all dependencies, i found:

dpkg: dependency problems prevent configuration of icedtea-netx:    

icedtea-netx depends on openjdk-6-jre (>= 6b23~pre10~) | openjdk-7-jre; however:   
Package openjdk-6-jre is not installed.  
Package openjdk-7-jre is not installed.

dpkg: error processing icedtea-netx (--configure):

dependency problems - leaving unconfigured

dpkg: dependency problems prevent configuration of bleachbit:

bleachbit depends on python-central (>= 0.6.7); however:

  Package python-central is not installed.

  bleachbit depends on menu; however:

  Package menu is not installed.


dpkg: error processing bleachbit (--configure):

 dependency problems - leaving unconfigured

dpkg: dependency problems prevent configuration of ca-certificates-java:

 ca-certificates-java depends on openjdk-6-jre-headless (>= 6b16-1.6.1-2) | java6-runtime-headless; however:

  Package openjdk-6-jre-headless is not installed.

  Package java6-runtime-headless is not installed.

dpkg: error processing ca-certificates-java (--configure):
 dependency problems - leaving unconfigured

dpkg: dependency problems prevent configuration of icedtea-6-plugin:

 icedtea-6-plugin depends on openjdk-6-jre; however:  Package openjdk-6-jre is not installed.   icedtea-6-plugin depends on icedtea-netx (= 1.2-2ubuntu1); however:
 Package icedtea-netx is not configured yet.



dpkg: error processing icedtea-6-plugin (--configure):

 dependency problems - leaving unconfigured

Errors were encountered while processing:

    icedtea-netx

    bleachbit

    ca-certificates-java

    icedtea-6-plugin

When I open ubuntu soft. center to install/remove any packages I also get this error:

Package dependencies cannot be resolved

The following packages have unmet dependencies:

bleachbit: Depends: python (>= 2.4) but 2.7.3-0ubuntu2 is installed
       Depends: python-gtk2 (>= 2.6) but 2.24.0-3 is installed
       Depends: python-central (>= 0.6.7) but it is not installed
       Depends: menu but it is not installed

 ca-certificates-java: Depends: java6-runtime-headless but it is a virtual package
 icedtea-6-plugin: Depends: openjdk-6-jre but it is not installed
              Depends: icedtea-netx (= 1.2-2ubuntu1) but 1.2-2ubuntu1 is installed
              Depends: libc6 (>= 2.4) but 2.15-0ubuntu10.3 is installed
              Depends: libgcc1 (>= 1:4.1.1) but 1:4.6.3-1ubuntu5 is installed
              Depends: libglib2.0-0 (>= 2.31.8) but 2.32.3-0ubuntu1 is installed
              Depends: libgtk2.0-0 (>= 2.8.0) but 2.24.10-0ubuntu6 is installed
              Depends: libstdc++6 (>= 4.6) but 4.6.3-1ubuntu5 is installed

  icedtea-netx: Depends: icedtea-netx-common (>= 1.2-2ubuntu1) but 1.2-2ubuntu1 is installed
          Depends: openjdk-7-jre but it is not installed

Solution 1

Try to install manual openjdk-6-jre (sudo apt-get install openjdk-6-jre) - when it is not possible run "apt-cache policy openjdk-6-jre" to see if you have a source for it. When you don’t have a source you miss universe and/or security sources in your /etc/apt/sources.list. Possible you miss also a "sudo apt-get update"?

or try to remove the packages with:

sudo dpkg --purge bleachbit ca-certificates-java icedtea-6-plugin icedtea-netx

Then try again to install what you want to install or just install oracle java:

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer

Solution 2

I think you are confusing apt and dpkg. You get the message

Try 'apt-get -f install' with no packages (or specify a solution)

but instead of apt-get -f install you execute sudo dpkg --configure -a "to get the all dependencies". That is not what dpkg does.

From the manpage of dpkg:

   --configure package...|-a|--pending
          Configure a package which has been unpacked but not yet  config‐
          ured.   If  -a  or  --pending  is  given instead of package, all
          unpacked but unconfigured packages are configured.

That is not the matter here. Apparently dpkg is not able to configure some packages succesfully due to unmet dependencies---not because unpacking of packages had been interrupted for any reason. Resolving dependencies by installing missing packages lays in the realm of apt. From the apt-get manpage:

   -f, --fix-broken
       Fix; attempt to correct a system with broken dependencies in place.
       This option, when used with install/remove, can omit any packages
       to permit APT to deduce a likely solution. If packages are
       specified, these have to completely correct the problem. 

Therefore the command that comes at hand and which was advertised by the error message is:

sudo apt-get install -f

From the actual broken dependencies that are presented in your copy&paste I take that this simple command should do the trick. If not, refer to this question or post exact error messages from above command.

The cause of this might be that you did not do an apt-get update beforehand. The packages list that apt holds point to individual packages in the repository. When one or more packages are upgrade in the repository for any reasons then older packages will be purged. The dependent packages then point to packages that are not provided anymore.

You do not have to run apt-get update every time you do an install, but you may end up with a situation like this. However that's easily fixed by sudo apt-get update && sudo apt-get install -f.

Comments

[Alvar]

possible duplicate of How do I resolve unmet dependencies?

[totti]

try sudo apt-get -f install

[Gaurav Sharma]

I already search to solve unmet dependencies but all Q. have different kind of package that meet other dependency and also tried -f option when installing and removing.

[Alex R]

try sudo apt-get clean && sudo apt-get update && sudo apt-get install -f

[Johannes Kohnen]

BTW, the 'default way' to install Java is by installing the package default-jre and/or default-jdk. In most use cases that is painless.

[Johannes Kohnen]

I have up voted this answer. Firstly I'd try the solution from my answer and then explicitly remove 'offending' packages / install missing dependencies as @TCr suggests. Another way would be to spawn aptitude in a terminal a let it work out a resolution. (It will display red rows at the bottom; then press e to examine suggestions, press . or , until a suggestions seems ok and then execute that with ! and g.