diff --git a/build.gradle b/build.gradle
index e0843ad..6516161 100644
--- a/build.gradle
+++ b/build.gradle
@@ -23,9 +23,9 @@ repositories {
 }
 
 dependencies {
-    compile 'org.slf4j:slf4j-api:1.7.12+'
+    compile 'org.slf4j:slf4j-api:1.7.12'
     /* using the simple logger at runtime, no need for it at compile time though */
-    runtime 'org.slf4j:slf4j-simple:1.7.12+'
+    runtime 'org.slf4j:slf4j-simple:1.7.12'
 
     /* Used for processing yaml files inside of gems */
     compile 'com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.5.4'
@@ -33,8 +33,8 @@ dependencies {
     compile 'com.fasterxml.jackson.core:jackson-databind:2.5.4'
 
     /* shrinkwrap is used for digging into archives */
-    compile "org.jboss.shrinkwrap:shrinkwrap-bom:1.2.2+"
-    compile "org.jboss.shrinkwrap:shrinkwrap-depchain:1.2.2+"
+    compile "org.jboss.shrinkwrap:shrinkwrap-bom:1.2.2"
+    compile "org.jboss.shrinkwrap:shrinkwrap-depchain:1.2.2"
 
     testCompile "org.spockframework:spock-core:1.0-groovy-2.4"
     testCompile 'org.apache.commons:commons-io:1.3.2+'
diff --git a/gem/jems.gemspec b/gem/jems.gemspec
new file mode 100644
index 0000000..8a7aa1e
--- /dev/null
+++ b/gem/jems.gemspec
@@ -0,0 +1,14 @@
+#-*- mode: ruby -*-
+
+Gem::Specification.new do |s|
+  s.name = 'jems'
+  s.version = '0.1.5'
+  s.authors = ['Christian Meier']
+  s.summary = 'JRuby Jems'
+  s.files = ['jems.gemspec', 'lib/jems.rb']
+  s.platform = 'java'
+  s.requirements << "jar com.github.jrubygradle:jem, #{s.version}"
+  s.add_runtime_dependency 'jar-dependencies', '~> 0.1.15'
+end
+
+# vim: syntax=Ruby
diff --git a/gem/lib/jems.rb b/gem/lib/jems.rb
new file mode 100644
index 0000000..f98fdde
--- /dev/null
+++ b/gem/lib/jems.rb
@@ -0,0 +1,34 @@
+require 'jems_jars'
+module Jems
+
+  def self.jems_class_loader
+    @class_loader ||= com.github.jrubygradle.jem.JemsClassLoader.create
+  end
+
+  def self.activate( gem )
+    gemspec_raw = jems_class_loader.add_jem( gem )
+    gemspec = eval( gemspec_raw.to_ruby )
+
+    return false if Gem.loaded_specs[ gemspec.name ]
+
+    gem_name = 'gems/' + gemspec.full_name + '/.jrubydir'
+    url = jems_class_loader.get_resource( gem_name )
+    base = "uri:#{url.to_s.sub(/.jrubydir$/, '')}"
+
+    added = false
+    gemspec.require_paths.each do |path|
+      fullpath = File.join( base, path )
+      if File.directory?(fullpath) and not $LOAD_PATH.member?(fullpath)
+        # TODO rubygems insert before 'site_ruby' entry of the LOAD_PATH
+        $LOAD_PATH.unshift fullpath
+        added = true
+      end
+    end
+    # TODO check if gemspec.activate does the job better
+    if added
+      Gem.loaded_specs[ gemspec.name ] = gemspec
+    end
+    added
+  end
+
+end
diff --git a/src/main/java/groovy/com/github/jrubygradle/jem/Dependency.java b/src/main/java/com/github/jrubygradle/jem/Dependency.java
similarity index 100%
rename from src/main/java/groovy/com/github/jrubygradle/jem/Dependency.java
rename to src/main/java/com/github/jrubygradle/jem/Dependency.java
diff --git a/src/main/java/groovy/com/github/jrubygradle/jem/Gem.java b/src/main/java/com/github/jrubygradle/jem/Gem.java
similarity index 99%
rename from src/main/java/groovy/com/github/jrubygradle/jem/Gem.java
rename to src/main/java/com/github/jrubygradle/jem/Gem.java
index 45fb33b..d66b089 100644
--- a/src/main/java/groovy/com/github/jrubygradle/jem/Gem.java
+++ b/src/main/java/com/github/jrubygradle/jem/Gem.java
@@ -7,7 +7,6 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
 
 import java.io.File;
-import java.io.IOError;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
diff --git a/src/main/java/groovy/com/github/jrubygradle/jem/GemInstaller.java b/src/main/java/com/github/jrubygradle/jem/GemInstaller.java
similarity index 100%
rename from src/main/java/groovy/com/github/jrubygradle/jem/GemInstaller.java
rename to src/main/java/com/github/jrubygradle/jem/GemInstaller.java
diff --git a/src/main/java/com/github/jrubygradle/jem/JemsClassLoader.java b/src/main/java/com/github/jrubygradle/jem/JemsClassLoader.java
new file mode 100644
index 0000000..473f166
--- /dev/null
+++ b/src/main/java/com/github/jrubygradle/jem/JemsClassLoader.java
@@ -0,0 +1,50 @@
+package com.github.jrubygradle.jem;
+
+import com.github.jrubygradle.jem.internal.GemInstaller;
+import com.github.jrubygradle.jem.GemInstaller.DuplicateBehavior;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Files;
+import java.util.Collections;
+
+/**
+ * Created by cmeier on 8/15/15.
+ */
+public class JemsClassLoader extends URLClassLoader {
+
+    private final File jemsDir;
+
+    public static JemsClassLoader create() throws IOException {
+        return new JemsClassLoader(Files.createTempDirectory("jems").toFile());
+    }
+
+    public JemsClassLoader(File jemsDir) throws IOException {
+        super(new URL[] { jemsDir.toURI().toURL() });
+        this.jemsDir = jemsDir;
+    }
+
+    public Gem addJem(String jem) throws IOException {
+        return addJem(new File(jem));
+    }
+    public Gem addJem(File jem) throws IOException {
+        GemInstaller installer = new GemInstaller(jemsDir.getAbsolutePath(), Collections.<File>emptyList());
+        installer.mkdirs();
+        Gem gemspec = installer.installGem(jemsDir, jem, DuplicateBehavior.OVERWRITE);
+        String dir = "gems/" + installer.gemFullName(gemspec);
+        createDirInfoFile(dir);
+        for(String path: gemspec.requirePaths){
+            createDirInfoFile(dir + "/" + path);
+        }
+        return gemspec;
+    }
+
+    private void createDirInfoFile(String dir) throws IOException {
+        try (FileWriter out = new FileWriter(new File(jemsDir, dir + "/.jrubydir"))){
+            out.append(".");
+        }
+    }
+}
diff --git a/src/main/java/groovy/com/github/jrubygradle/jem/Requirement.java b/src/main/java/com/github/jrubygradle/jem/Requirement.java
similarity index 100%
rename from src/main/java/groovy/com/github/jrubygradle/jem/Requirement.java
rename to src/main/java/com/github/jrubygradle/jem/Requirement.java
diff --git a/src/main/java/groovy/com/github/jrubygradle/jem/Version.java b/src/main/java/com/github/jrubygradle/jem/Version.java
similarity index 100%
rename from src/main/java/groovy/com/github/jrubygradle/jem/Version.java
rename to src/main/java/com/github/jrubygradle/jem/Version.java
diff --git a/src/main/java/groovy/com/github/jrubygradle/jem/internal/GemInstaller.java b/src/main/java/com/github/jrubygradle/jem/internal/GemInstaller.java
similarity index 97%
rename from src/main/java/groovy/com/github/jrubygradle/jem/internal/GemInstaller.java
rename to src/main/java/com/github/jrubygradle/jem/internal/GemInstaller.java
index 9782a32..df464c6 100644
--- a/src/main/java/groovy/com/github/jrubygradle/jem/internal/GemInstaller.java
+++ b/src/main/java/com/github/jrubygradle/jem/internal/GemInstaller.java
@@ -50,14 +50,14 @@ public class GemInstaller {
         }
     }
 
-    public boolean installGem(File installDir, File gem, DuplicateBehavior onDuplicate) {
+    public Gem installGem(File installDir, File gem, DuplicateBehavior onDuplicate) {
         /* TODO: isValidGem? */
         try {
             cacheGemInInstallDir(installDir, gem);
         }
         catch (IOException ex) {
             logger.error("Failed to cache our gem in %s", installDir, ex);
-            return false;
+            return null;
         }
 
         Gem gemMetadata;
@@ -73,7 +73,7 @@ public class GemInstaller {
         }
         catch (IOException ex) {
             logger.error("Failed to process the metadata", ex);
-            return false;
+            return null;
         }
         logger.info(String.format("We've processed metadata for %s at version %s",
                 gemMetadata.name, gemMetadata.version.version));
@@ -96,7 +96,7 @@ public class GemInstaller {
                     gemMetadata.name, installDir), ex);
         }
 
-        return true;
+        return gemMetadata;
     }
 
     /**
diff --git a/src/test/groovy/com/github/jrubygradle/jem/internal/GemInstallerSpec.groovy b/src/test/groovy/com/github/jrubygradle/jem/internal/GemInstallerSpec.groovy
index a30a107..b2ea2d2 100644
--- a/src/test/groovy/com/github/jrubygradle/jem/internal/GemInstallerSpec.groovy
+++ b/src/test/groovy/com/github/jrubygradle/jem/internal/GemInstallerSpec.groovy
@@ -6,7 +6,6 @@ import spock.lang.*
 
 import java.nio.file.Files
 import java.nio.file.Path
-import org.apache.commons.io.FileUtils
 
 class GemInstallerSpec extends Specification {
     static final String FIXTURES_ROOT = new File(['src', 'test', 'resources'].join(File.separator)).absolutePath