In **Ubuntu 14.04**, try the following:

    sudo apt-get install rubygems-integration



I have an Android Project in Android Studio 0.5.9 and Gradle is throwing this error:

    Error:The SDK Build Tools revision (17.0.0) is too low. Minimum required is 19.0.0

I have already installed SDK Build Tools Revision 19 from the SDK Manager and here is my build.gradle


    buildscript {
        repositories {
            mavenCentral()
        }
        dependencies {
            classpath &#39;com.android.tools.build:gradle:0.10.+&#39;
        }
    }
    apply plugin: &#39;android&#39;
    
    repositories {
        mavenCentral()
    }
    
    android {
        compileSdkVersion 17
        buildToolsVersion &quot;19.0.0&quot;
    
        defaultConfig {
            minSdkVersion 9
            targetSdkVersion 17
        }
    
        sourceSets {
            main {
                manifest.srcFile &#39;Manantiales/src/main/AndroidManifest.xml&#39;
            }
        }
    }

How do I tell gradle to use the Build Tools 19 if it&#39;s already installed?

EDIT: I marked a different answer as The Best Answer because it was the one that worked for most people


Android Studio Gradle BuildTools Revision

There are various articles out there on the interwebs that try to empirically estimate the overhead of a `java.lang.Object` in particular JVM implementations. For example, I&#39;ve seen the size overhead of a bare `Object` [estimated at 8 bytes](http://www.javamex.com/tutorials/memory/object_memory_usage.shtml) in some JVMs.

What I would like to know is whether a typical JVM implementation of the `extends` relationship introduces incremental size overhead at every level of the class hierarchy. In other words, suppose you have a class hierarchy with N levels of subclasses. Is the overhead of the in-memory representation of a class instance O(1) or O(N)?

I imagine it is O(1) because although the size of some of the hidden fluffy stuff you need to be a Java `Object` (vtable, chain of classes) will grow as the inheritance hierarchy grows, they grow per-class, not per-instance, and the JVM implementation can store constant-size pointers to these entities in a constant-size header attached to every `Object`.

So in theory, the overhead directly attached to the in-memory representation of any Java object should be O(1) for inheritance depth N. Does anyone know if it&#39;s true in practice?

What&#39;s the size cost of Java inheritance?

Hi I would appreciate some help installing rubygems. This is what happens when I try. &quot;ruby-full&quot; has already been installed. How do I fix this? What is the issue?

    $ sudo apt-get install rubygems 
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    Package rubygems is not available, but is referred to by another package.
    This may mean that the package is missing, has been obsoleted, or
    is only available from another source
    However the following packages replace it:
      ruby
    
    E: Package &#39;rubygems&#39; has no installation candidate

I am running Ubuntu 14.04. Ruby version installed: 1:1.9.3.4. Please let me know if there are any other additional details that could help solve this issue.

Install Error: &#39;rubygems&#39; has no installation candidate

Hi I would appreciate some help installing rubygems. This is what happens when I try. "ruby-full" has already been installed. How do I fix this? What is the issue?
<pre><code class="hljs language-kotlin">$ sudo apt-get install rubygems 
Reading package lists... Done
Building dependency tree 
Reading state information... Done
Package rubygems is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
 ruby

E: Package 'rubygems' has no installation candidate
</code></pre>
I am running Ubuntu 14.04. Ruby version installed: 1:1.9.3.4. Please let me know if there are any other additional details that could help solve this issue.

I don&#39;t manage to install therubyracer gem on Yosemite 10.10.

Here is the log:

&lt;pre&gt;
11:53  $ gem install libv8 -v &#39;3.16.14.3&#39; -- --with-system-v8


Building native extensions with: &#39;--with-system-v8&#39;
This could take a while...
Successfully installed libv8-3.16.14.3
Parsing documentation for libv8-3.16.14.3
Installing ri documentation for libv8-3.16.14.3
Done installing documentation for libv8 after 0 seconds
1 gem installed


02:05  $ gem install therubyracer -v &#39;0.12.1&#39; -- --with-system-v8


Building native extensions with: &#39;--with-system-v8&#39;
This could take a while...
ERROR:  Error installing therubyracer:
	ERROR: Failed to build gem native extension.

    /usr/local/var/rbenv/versions/2.1.2/bin/ruby extconf.rb --with-system-v8
checking for main() in -lpthread... yes
checking for main() in -lobjc... yes
checking for v8.h... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
	--with-opt-dir
	--without-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/usr/local/var/rbenv/versions/2.1.2/bin/ruby
	--with-pthreadlib
	--without-pthreadlib
	--with-objclib
	--without-objclib
	--enable-debug
	--disable-debug
	--with-v8-dir
	--without-v8-dir
	--with-v8-include
	--without-v8-include=${v8-dir}/include
	--with-v8-lib
	--without-v8-lib=${v8-dir}/lib
/usr/local/var/rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/libv8-3.16.14.3/ext/libv8/location.rb:50:in `configure&#39;: You have chosen to use the version of V8 found on your system (Libv8::Location::System::NotFoundError)
and *not* the one that is bundle with the libv8 rubygem. However,
it could not be located. please make sure you have a version of
v8 that is compatible with 3.16.14.3 installed. You may
need to special --with-v8-dir options if it is in a non-standard
location

thanks,
The Mgmt

	from /usr/local/var/rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/libv8-3.16.14.3/lib/libv8.rb:7:in `configure_makefile&#39;
	from extconf.rb:32:in `&lt;main&gt;&#39;

extconf failed, exit code 1

Gem files will remain installed in /usr/local/var/rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/therubyracer-0.12.1 for inspection.
Results logged to /usr/local/var/rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-14/2.1.0-static/therubyracer-0.12.1/gem_make.out
&lt;/pre&gt;

How to install therubyracer gem on 10.10 Yosemite?

I know there are a lot of questions about this gem but no answer has worked for me.

When I run in SSH `gem install nokogiri` I get this error:

    Extracting libxml2-2.8.0.tar.gz into tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0... OK
    Running patch with /home/user58952277/.gem/ruby/1.9.3/gems/nokogiri-1.6.2.1/ports/patches/libxml2/0001-Fix-parser-local-buffers-size-problems.patch...
    Running &#39;patch&#39; for libxml2 2.8.0... ERROR, review &#39;tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0/patch.log&#39; to see what happened.
    *** extconf.rb failed ***
    Could not create Makefile due to some reason, probably lack of
    necessary libraries and/or headers.  Check the mkmf.log file for more
    details.  You may need configuration options.

My host told me that all libs are installed.
Here are the full logs after executing the install nokogiri command:

    Building native extensions.  This could take a while...
    Building nokogiri using packaged libraries.
    Building libxml2-2.8.0 for nokogiri with the following patches applied:
    	- 0001-Fix-parser-local-buffers-size-problems.patch
    	- 0002-Fix-entities-local-buffers-size-problems.patch
    	- 0003-Fix-an-error-in-previous-commit.patch
    	- 0004-Fix-potential-out-of-bound-access.patch
    	- 0005-Detect-excessive-entities-expansion-upon-replacement.patch
    	- 0006-Do-not-fetch-external-parsed-entities.patch
    	- 0007-Enforce-XML_PARSER_EOF-state-handling-through-the-pa.patch
    	- 0008-Improve-handling-of-xmlStopParser.patch
    	- 0009-Fix-a-couple-of-return-without-value.patch
    	- 0010-Keep-non-significant-blanks-node-in-HTML-parser.patch
    	- 0011-Do-not-fetch-external-parameter-entities.patch
    ************************************************************************
    IMPORTANT!  Nokogiri builds and uses a packaged version of libxml2.
    
    If this is a concern for you and you want to use the system library
    instead, abort this installation process and reinstall nokogiri as
    follows:
    
        gem install nokogiri -- --use-system-libraries
    
    If you are using Bundler, tell it to use the option:
    
        bundle config build.nokogiri --use-system-libraries
        bundle install
    
    However, note that nokogiri does not necessarily support all versions
    of libxml2.
    
    For example, libxml2-2.9.0 and higher are currently known to be broken
    and thus unsupported by nokogiri, due to compatibility problems and
    XPath optimization bugs.
    ************************************************************************
    ERROR:  Error installing nokogiri:
    	ERROR: Failed to build gem native extension.
    
            /opt/rubies/ruby-1.9.3/bin/ruby extconf.rb
    Building nokogiri using packaged libraries.
    checking for iconv.h... yes
    checking for iconv_open() in iconv.h... yes
    Building libxml2-2.8.0 for nokogiri with the following patches applied:
    	- 0001-Fix-parser-local-buffers-size-problems.patch
    	- 0002-Fix-entities-local-buffers-size-problems.patch
    	- 0003-Fix-an-error-in-previous-commit.patch
    	- 0004-Fix-potential-out-of-bound-access.patch
    	- 0005-Detect-excessive-entities-expansion-upon-replacement.patch
    	- 0006-Do-not-fetch-external-parsed-entities.patch
    	- 0007-Enforce-XML_PARSER_EOF-state-handling-through-the-pa.patch
    	- 0008-Improve-handling-of-xmlStopParser.patch
    	- 0009-Fix-a-couple-of-return-without-value.patch
    	- 0010-Keep-non-significant-blanks-node-in-HTML-parser.patch
    	- 0011-Do-not-fetch-external-parameter-entities.patch
    ************************************************************************
    IMPORTANT!  Nokogiri builds and uses a packaged version of libxml2.
    
    If this is a concern for you and you want to use the system library
    instead, abort this installation process and reinstall nokogiri as
    follows:
    
        gem install nokogiri -- --use-system-libraries
    
    If you are using Bundler, tell it to use the option:
    
        bundle config build.nokogiri --use-system-libraries
        bundle install
    
    However, note that nokogiri does not necessarily support all versions
    of libxml2.
    
    For example, libxml2-2.9.0 and higher are currently known to be broken
    and thus unsupported by nokogiri, due to compatibility problems and
    XPath optimization bugs.
    ************************************************************************
    Extracting libxml2-2.8.0.tar.gz into tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0... OK
    Running patch with /home/user58952277/.gem/ruby/1.9.3/gems/nokogiri-1.6.2.1/ports/patches/libxml2/0001-Fix-parser-local-buffers-size-problems.patch...
    Running &#39;patch&#39; for libxml2 2.8.0... ERROR, review &#39;tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0/patch.log&#39; to see what happened.
    *** extconf.rb failed ***
    Could not create Makefile due to some reason, probably lack of
    necessary libraries and/or headers.  Check the mkmf.log file for more
    details.  You may need configuration options.
    
    Provided configuration options:
    	--with-opt-dir
    	--without-opt-dir
    	--with-opt-include
    	--without-opt-include=${opt-dir}/include
    	--with-opt-lib
    	--without-opt-lib=${opt-dir}/lib
    	--with-make-prog
    	--without-make-prog
    	--srcdir=.
    	--curdir
    	--ruby=/opt/rubies/ruby-1.9.3/bin/ruby
    	--help
    	--clean
    	--use-system-libraries
    	--enable-static
    	--disable-static
    	--with-zlib-dir
    	--without-zlib-dir
    	--with-zlib-include
    	--without-zlib-include=${zlib-dir}/include
    	--with-zlib-lib
    	--without-zlib-lib=${zlib-dir}/lib
    	--enable-cross-build
    	--disable-cross-build
    /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:279:in `block in execute&#39;: Failed to complete patch task (RuntimeError)
    	from /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:271:in `chdir&#39;
    	from /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:271:in `execute&#39;
    	from extconf.rb:282:in `block in patch&#39;
    	from extconf.rb:279:in `each&#39;
    	from extconf.rb:279:in `patch&#39;
    	from /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:108:in `cook&#39;
    	from extconf.rb:253:in `block in process_recipe&#39;
    	from extconf.rb:154:in `tap&#39;
    	from extconf.rb:154:in `process_recipe&#39;
    	from extconf.rb:419:in `&lt;main&gt;&#39;




nokogiri gem installation error

I&#39;m getting an error when I run  `brew` in the terminal:

     /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require&#39;: cannot load such file -- utils/popen (LoadError)
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require&#39;
    from /usr/local/Library/Homebrew/utils.rb:6:in `&lt;top (required)&gt;&#39;
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require&#39;
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require&#39;
    from /usr/local/Library/Homebrew/global.rb:9:in `&lt;top (required)&gt;&#39;
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require&#39;
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require&#39;
    from /usr/local/Library/brew.rb:16:in `&lt;main&gt;&#39;


These are my gem settings:

    - RUBYGEMS VERSION: 2.0.14
    - RUBY VERSION: 2.0.0 (2014-02-24 patchlevel 451) [universal.x86_64-darwin13]
    - INSTALLATION DIRECTORY: /Library/Ruby/Gems/2.0.0
    - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
    - EXECUTABLE DIRECTORY: /usr/bin
    - RUBYGEMS PLATFORMS:
      - ruby
      - universal-darwin-13
    - GEM PATHS:
      - /Library/Ruby/Gems/2.0.0
      - /Users/ronaldkwan/.gem/ruby/2.0.0
      - /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/gems/2.0.0
    - GEM CONFIGURATION:
      - :update_sources =&gt; true
      - :verbose =&gt; true
      - :backtrace =&gt; false
      - :bulk_threshold =&gt; 1000


How to avoid &quot;cannot load such file -- utils/popen&quot; from homebrew on OSX

I am not able to install and run `fakes3` gem on El Capitan Beta 5.

I tried:

    sudo gem install fakes3
    ERROR:  While executing gem ... (Errno::EPERM)
        Operation not permitted - /usr/bin/fakes3

Then I tried doing it the cocoapods way. It worked for cocoapods but not for fakes3.

    mkdir -p $HOME/Software/ruby
    export GEM_HOME=$HOME/Software/ruby
    gem install cocoapods
    [...]
    1 gem installed
    gem install fakes3
    ERROR:  While executing gem ... (Gem::FilePermissionError)
        You don&#39;t have write permissions for the /Library/Ruby/Gems/2.0.0 directory.

Can&#39;t install gems on OS X &quot;El Capitan&quot;

I just updated my Mac to OSX 10.11 El Capitan and some gems didn&#39;t remain.

The problem arose when I tried to run installations of different gems... e.g.:

    &gt; sudo gem install compass

Once I execute, I get the error:

    &gt; ERROR:  While executing gem ... (Errno::EPERM) Operation not permitted

This happens with other gems, as well...

I&#39;ve run Homebrew and tried to install Ruby again, but nothing is working.

Content Type	Original Author	Original Content on Stackoverflow
Question	JasoonS	View Question on Stackoverflow
Solution 1 - Rubygems	Govind	View Answer on Stackoverflow

Install Error: 'rubygems' has no installation candidate

Rubygems Problem Overview

Rubygems Solutions

Solution 1 - Rubygems

What's the size cost of Java inheritance?

Android Studio Gradle BuildTools Revision

Attributions