diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPQuestion.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPQuestion.java
index 4f57ce9c..e0e6ef40 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPQuestion.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPQuestion.java
@@ -48,5 +48,5 @@ public interface MPQuestion extends Comparable<MPQuestion> {
     // -- Relationship
 
     @Nonnull
-    MPSite getSite();
+    MPSite<?> getSite();
 }
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSite.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSite.java
index d11b5667..77498ad9 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSite.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSite.java
@@ -27,7 +27,7 @@ import javax.annotation.Nullable;
 /**
  * @author lhunath, 2018-05-14
  */
-public interface MPSite<Q extends MPQuestion> extends Comparable<MPSite<Q>> {
+public interface MPSite<Q extends MPQuestion> extends Comparable<MPSite<?>> {
 
     // - Meta
 
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSiteResult.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSiteResult.java
index c5845e22..c4b98356 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSiteResult.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPSiteResult.java
@@ -29,13 +29,13 @@ import org.jetbrains.annotations.NotNull;
  */
 public class MPSiteResult implements Comparable<MPSiteResult> {
 
-    private final MPSite site;
+    private final MPSite<?> site;
 
-    public MPSiteResult(final MPSite site) {
+    public MPSiteResult(final MPSite<?> site) {
         this.site = site;
     }
 
-    public MPSite getSite() {
+    public MPSite<?> getSite() {
         return site;
     }
 
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUser.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUser.java
index 63be260c..ca54cc08 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUser.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUser.java
@@ -27,7 +27,7 @@ import javax.annotation.Nullable;
 /**
  * @author lhunath, 2018-05-14
  */
-public interface MPUser<S extends MPSite> extends Comparable<MPUser<?>> {
+public interface MPUser<S extends MPSite<?>> extends Comparable<MPUser<?>> {
 
     // - Meta
 
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUserManager.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUserManager.java
index 308c1df1..5a790b10 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUserManager.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/MPUserManager.java
@@ -19,8 +19,8 @@
 package com.lyndir.masterpassword.model;
 
 import com.google.common.collect.*;
-import java.util.Map;
-import java.util.SortedSet;
+import java.util.*;
+import java.util.stream.Collectors;
 
 
 /**
@@ -35,8 +35,8 @@ public abstract class MPUserManager<U extends MPUser<?>> {
             usersByName.put( user.getFullName(), user );
     }
 
-    public SortedSet<U> getUsers() {
-        return FluentIterable.from( usersByName.values() ).toSortedSet( Ordering.natural() );
+    public Collection<U> getUsers() {
+        return ImmutableList.copyOf( usersByName.values() );
     }
 
     public U getUserNamed(final String fullName) {
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicQuestion.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicQuestion.java
index 7f072ebd..4d91cb45 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicQuestion.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicQuestion.java
@@ -68,7 +68,7 @@ public abstract class MPBasicQuestion implements MPQuestion {
 
     @Nonnull
     @Override
-    public abstract MPBasicSite getSite();
+    public abstract MPBasicSite<?> getSite();
 
     @Override
     public int hashCode() {
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicSite.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicSite.java
index 288495a2..abb774a2 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicSite.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicSite.java
@@ -164,7 +164,7 @@ public abstract class MPBasicSite<Q extends MPQuestion> implements MPSite<Q> {
     }
 
     @Override
-    public int compareTo(@NotNull final MPSite<Q> o) {
+    public int compareTo(@NotNull final MPSite<?> o) {
         return getName().compareTo( o.getName() );
     }
 
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicUser.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicUser.java
index f73aa33e..66949190 100755
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicUser.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicUser.java
@@ -33,7 +33,7 @@ import javax.annotation.Nullable;
 /**
  * @author lhunath, 2014-06-08
  */
-public abstract class MPBasicUser<S extends MPBasicSite> implements MPUser<S> {
+public abstract class MPBasicUser<S extends MPBasicSite<?>> implements MPUser<S> {
 
     private       int         avatar;
     private final String      fullName;
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileSite.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileSite.java
index b833c410..b105f6a2 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileSite.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileSite.java
@@ -20,8 +20,6 @@ package com.lyndir.masterpassword.model.impl;
 
 import com.google.common.primitives.UnsignedInteger;
 import com.lyndir.masterpassword.*;
-import com.lyndir.masterpassword.model.MPSite;
-import com.lyndir.masterpassword.model.MPUser;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import org.joda.time.Instant;
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileUserManager.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileUserManager.java
index 4bc1073f..bcb06431 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileUserManager.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileUserManager.java
@@ -96,15 +96,12 @@ public class MPFileUserManager extends MPUserManager<MPFileUser> {
     }
 
     private static ImmutableList<File> listUserFiles(final File userFilesDirectory) {
-        return ImmutableList.copyOf( ifNotNullElse( userFilesDirectory.listFiles( new FilenameFilter() {
-            @Override
-            public boolean accept(final File dir, final String name) {
-                for (final MPMarshalFormat format : MPMarshalFormat.values())
-                    if (name.endsWith( format.fileSuffix() ))
-                        return true;
+        return ImmutableList.copyOf( ifNotNullElse( userFilesDirectory.listFiles( (dir, name) -> {
+            for (final MPMarshalFormat format : MPMarshalFormat.values())
+                if (name.endsWith( format.fileSuffix() ))
+                    return true;
 
-                return false;
-            }
+            return false;
         } ), new File[0] ) );
     }
 
@@ -124,7 +121,7 @@ public class MPFileUserManager extends MPUserManager<MPFileUser> {
     public void save(final MPFileUser user, final MPMasterKey masterKey)
             throws MPKeyUnavailableException {
         try {
-            final MPMarshalFormat format = user.getFormat();
+            MPMarshalFormat format = user.getFormat();
             new CharSink() {
                 @Override
                 public Writer openStream()
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFlatUnmarshaller.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFlatUnmarshaller.java
index f50cac07..0d513be6 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFlatUnmarshaller.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFlatUnmarshaller.java
@@ -33,6 +33,7 @@ import java.util.regex.Pattern;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import org.joda.time.DateTime;
+import org.joda.time.Instant;
 
 
 /**
@@ -77,7 +78,7 @@ public class MPFlatUnmarshaller implements MPUnmarshaller {
                 else
                     // Ends the header.
                     user = new MPFileUser( fullName, keyID, MPAlgorithm.Version.fromInt( mpVersion ).getAlgorithm(),
-                                           avatar, defaultType, new DateTime( 0 ), MPMarshalFormat.Flat,
+                                           avatar, defaultType, new Instant( 0 ), MPMarshalFormat.Flat,
                                            clearContent? MPMarshaller.ContentMode.VISIBLE: MPMarshaller.ContentMode.PROTECTED );
 
                 // Comment.
diff --git a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPMarshaller.java b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPMarshaller.java
index 7f6c84cc..8f881d67 100644
--- a/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPMarshaller.java
+++ b/core/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPMarshaller.java
@@ -25,6 +25,7 @@ import javax.annotation.Nonnull;
 /**
  * @author lhunath, 14-12-07
  */
+@FunctionalInterface
 public interface MPMarshaller {
 
     @Nonnull
diff --git a/platform-android/src/main/java/com/lyndir/masterpassword/Preferences.java b/platform-android/src/main/java/com/lyndir/masterpassword/Preferences.java
index 271513dc..c792cb98 100644
--- a/platform-android/src/main/java/com/lyndir/masterpassword/Preferences.java
+++ b/platform-android/src/main/java/com/lyndir/masterpassword/Preferences.java
@@ -86,7 +86,7 @@ public final class Preferences {
     }
 
     public Set<String> getTestsPassed() {
-        return prefs().getStringSet( PREF_TESTS_PASSED, ImmutableSet.<String>of() );
+        return prefs().getStringSet( PREF_TESTS_PASSED, ImmutableSet.of() );
     }
 
     public boolean setRememberFullName(final boolean enabled) {
diff --git a/platform-android/src/main/java/com/lyndir/masterpassword/TestActivity.java b/platform-android/src/main/java/com/lyndir/masterpassword/TestActivity.java
index c82dda30..8283441f 100644
--- a/platform-android/src/main/java/com/lyndir/masterpassword/TestActivity.java
+++ b/platform-android/src/main/java/com/lyndir/masterpassword/TestActivity.java
@@ -28,13 +28,12 @@ import android.view.View;
 import android.widget.*;
 import butterknife.BindView;
 import butterknife.ButterKnife;
-import com.google.common.base.Function;
-import com.google.common.base.Predicates;
-import com.google.common.collect.FluentIterable;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.util.concurrent.*;
 import com.lyndir.lhunath.opal.system.logging.Logger;
+import java.util.Objects;
+import java.util.Set;
 import java.util.concurrent.Executors;
+import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 
 
@@ -67,7 +66,7 @@ public class TestActivity extends Activity implements MPTestSuite.Listener {
     private ListenableFuture<Boolean> testFuture;
     @Nullable
     private Runnable                  action;
-    private ImmutableSet<String>      testNames;
+    private Set<String>               testNames;
 
     public static void startNoSkip(final Context context) {
         context.startActivity( new Intent( context, TestActivity.class ) );
@@ -80,35 +79,22 @@ public class TestActivity extends Activity implements MPTestSuite.Listener {
         setContentView( R.layout.activity_test );
         ButterKnife.bind( this );
 
-        nativeKDFField.setOnCheckedChangeListener( new CompoundButton.OnCheckedChangeListener() {
-            @Override
-            public void onCheckedChanged(final CompoundButton buttonView, final boolean isChecked) {
-                preferences.setNativeKDFEnabled( isChecked );
-                // TODO: MasterKey.setAllowNativeByDefault( isChecked );
-            }
+        nativeKDFField.setOnCheckedChangeListener( (buttonView, isChecked) -> {
+            preferences.setNativeKDFEnabled( isChecked );
+            // TODO: MasterKey.setAllowNativeByDefault( isChecked );
         } );
 
         try {
             setStatus( 0, 0, null );
             testSuite = new MPTestSuite();
             testSuite.setListener( this );
-            testNames = FluentIterable.from( testSuite.getTests().getCases() ).transform(
-                    new Function<MPTests.Case, String>() {
-                        @Nullable
-                        @Override
-                        public String apply(@Nullable final MPTests.Case input) {
-                            return (input == null)? null: input.identifier;
-                        }
-                    } ).filter( Predicates.notNull() ).toSet();
+            testNames = testSuite.getTests().getCases().stream()
+                                 .map( input -> (input == null)? null: input.identifier )
+                                 .filter( Objects::nonNull ).collect( Collectors.toSet() );
         }
         catch (final MPTestSuite.UnavailableException e) {
             logger.err( e, "While loading test suite" );
-            setStatus( R.string.tests_unavailable, R.string.tests_btn_unavailable, new Runnable() {
-                @Override
-                public void run() {
-                    finish();
-                }
-            } );
+            setStatus( R.string.tests_unavailable, R.string.tests_btn_unavailable, this::finish );
         }
     }
 
@@ -133,31 +119,18 @@ public class TestActivity extends Activity implements MPTestSuite.Listener {
             @Override
             public void onSuccess(@Nullable final Boolean result) {
                 if ((result != null) && result)
-                    setStatus( R.string.tests_passed, R.string.tests_btn_passed, new Runnable() {
-                        @Override
-                        public void run() {
-                            preferences.setTestsPassed( testNames );
-                            finish();
-                        }
+                    setStatus( R.string.tests_passed, R.string.tests_btn_passed, () -> {
+                        preferences.setTestsPassed( testNames );
+                        finish();
                     } );
                 else
-                    setStatus( R.string.tests_failed, R.string.tests_btn_failed, new Runnable() {
-                        @Override
-                        public void run() {
-                            startTestSuite();
-                        }
-                    } );
+                    setStatus( R.string.tests_failed, R.string.tests_btn_failed, () -> startTestSuite() );
             }
 
             @Override
             public void onFailure(final Throwable t) {
                 logger.err( t, "While running test suite" );
-                setStatus( R.string.tests_failed, R.string.tests_btn_failed, new Runnable() {
-                    @Override
-                    public void run() {
-                        finish();
-                    }
-                } );
+                setStatus( R.string.tests_failed, R.string.tests_btn_failed, () -> finish() );
             }
         }, mainExecutor );
     }
@@ -184,14 +157,11 @@ public class TestActivity extends Activity implements MPTestSuite.Listener {
 
     @Override
     public void progress(final int current, final int max, final String messageFormat, final Object... args) {
-        runOnUiThread( new Runnable() {
-            @Override
-            public void run() {
-                logView.append( strf( "%n" + messageFormat, args ) );
+        runOnUiThread( () -> {
+            logView.append( strf( "%n" + messageFormat, args ) );
 
-                progressView.setMax( max );
-                progressView.setProgress( current );
-            }
+            progressView.setMax( max );
+            progressView.setProgress( current );
         } );
     }
 }
diff --git a/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/ModelAuthenticationPanel.java b/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/ModelAuthenticationPanel.java
index 9ae2d4e1..7d1bc9ed 100644
--- a/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/ModelAuthenticationPanel.java
+++ b/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/ModelAuthenticationPanel.java
@@ -189,15 +189,11 @@ public class ModelAuthenticationPanel extends AuthenticationPanel<MPFileUser> im
             }
         }, new JButton( Res.iconQuestion() ) {
             {
-                addActionListener( new ActionListener() {
-                    @Override
-                    public void actionPerformed(final ActionEvent e) {
-                        JOptionPane.showMessageDialog( ModelAuthenticationPanel.this, //
-                                                       strf( "Reads users and sites from the directory at:%n%s",
-                                                             MPFileUserManager.get().getPath().getAbsolutePath() ), //
-                                                       "Help", JOptionPane.INFORMATION_MESSAGE );
-                    }
-                } );
+                addActionListener( e -> JOptionPane.showMessageDialog(
+                        ModelAuthenticationPanel.this, //
+                        strf( "Reads users and sites from the directory at:%n%s",
+                              MPFileUserManager.get().getPath().getAbsolutePath() ), //
+                        "Help", JOptionPane.INFORMATION_MESSAGE ) );
                 setToolTipText( "More information." );
             }
         } );
diff --git a/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/PasswordFrame.java b/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/PasswordFrame.java
index f4aa5614..cd36c5b4 100755
--- a/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/PasswordFrame.java
+++ b/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/PasswordFrame.java
@@ -28,6 +28,7 @@ import com.lyndir.masterpassword.*;
 import com.lyndir.masterpassword.gui.Res;
 import com.lyndir.masterpassword.gui.util.Components;
 import com.lyndir.masterpassword.gui.util.UnsignedIntegerModel;
+import com.lyndir.masterpassword.model.MPSite;
 import com.lyndir.masterpassword.model.MPUser;
 import com.lyndir.masterpassword.model.impl.*;
 import java.awt.*;
@@ -46,7 +47,7 @@ import javax.swing.event.DocumentListener;
 /**
  * @author lhunath, 2014-06-08
  */
-public abstract class PasswordFrame<U extends MPUser<S>, S extends MPBasicSite> extends JFrame implements DocumentListener {
+public abstract class PasswordFrame<U extends MPUser<S>, S extends MPSite<?>> extends JFrame implements DocumentListener {
 
     @SuppressWarnings("FieldCanBeLocal")
     private final Components.GradientPanel       root;
diff --git a/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/UnlockFrame.java b/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/UnlockFrame.java
index ff9dbb69..f5a80aef 100644
--- a/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/UnlockFrame.java
+++ b/platform-independent/gui-java/src/main/java/com/lyndir/masterpassword/gui/view/UnlockFrame.java
@@ -48,7 +48,7 @@ public class UnlockFrame extends JFrame {
     private       Future<?>                identiconFuture;
     private       boolean                  incognito;
     @Nullable
-    private       MPUser<? extends MPSite> user;
+    private       MPUser<? extends MPSite<?>> user;
 
     public UnlockFrame(final SignInCallback signInCallback) {
         super( "Unlock Master Password" );
@@ -144,7 +144,7 @@ public class UnlockFrame extends JFrame {
         SwingUtilities.invokeLater( () -> ifNotNullElse( authenticationPanel.getFocusComponent(), signInButton ).requestFocusInWindow() );
     }
 
-    void updateUser(@Nullable final MPUser<? extends MPSite> user) {
+    void updateUser(@Nullable final MPUser<? extends MPSite<?>> user) {
         this.user = user;
         checkSignIn();
     }