Lint issues fixed

android-app/src/main/java/org/solovyev/android/calculator/AndroidCalculatorNotifier.java

@@ -25,15 +25,13 @@ package org.solovyev.android.calculator;
 import android.app.Application;
 import android.os.Handler;
 import android.widget.Toast;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
 import org.solovyev.android.Threads;
 import org.solovyev.android.msg.AndroidMessage;
 import org.solovyev.common.msg.Message;
 import org.solovyev.common.msg.MessageType;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.List;
 
 /**
@@ -56,7 +54,7 @@ public class AndroidCalculatorNotifier implements CalculatorNotifier {
 	}
 
 	public AndroidCalculatorNotifier(@Nonnull Application application, boolean showDebugMessages) {
-		assert Threads.isUiThread();
+		if (!Threads.isUiThread()) throw new AssertionError();
 
 		this.application = application;
 		this.showDebugMessages = showDebugMessages;

android-app/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java

@@ -22,6 +22,7 @@
 
 package org.solovyev.android.calculator;
 
+import android.annotation.TargetApi;
 import android.app.AlertDialog;
 import android.content.Context;
 import android.content.SharedPreferences;
@@ -96,7 +97,7 @@ public class CalculatorActivity extends SherlockFragmentActivity implements Shar
 			activityHelper.addTab(this, CalculatorPlotActivity.getPlotterFragmentType(), null, R.id.main_second_pane);
 		} else {
 			final ActionBar actionBar = getSupportActionBar();
-			if (Build.VERSION.SDK_INT <= GINGERBREAD_MR1 || (Build.VERSION.SDK_INT >= ICE_CREAM_SANDWICH && ViewConfiguration.get(this).hasPermanentMenuKey())) {
+			if (Build.VERSION.SDK_INT <= GINGERBREAD_MR1 || (Build.VERSION.SDK_INT >= ICE_CREAM_SANDWICH && hasPermanentMenuKey())) {
 				actionBar.hide();
 			} else {
 				actionBar.setDisplayShowTitleEnabled(false);
@@ -126,6 +127,11 @@ public class CalculatorActivity extends SherlockFragmentActivity implements Shar
 		}
 	}
 
+	@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
+	private boolean hasPermanentMenuKey() {
+		return ViewConfiguration.get(this).hasPermanentMenuKey();
+	}
+
 	private boolean isMultiPane() {
 		return findViewById(R.id.main_second_pane) != null;
 	}

android-app/src/main/java/org/solovyev/android/calculator/CalculatorActivityHelperImpl.java

@@ -36,17 +36,15 @@ import android.util.Log;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
-
 import com.actionbarsherlock.app.ActionBar;
 import com.actionbarsherlock.app.SherlockFragmentActivity;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
 import org.solovyev.android.Activities;
 import org.solovyev.android.Views;
 import org.solovyev.android.sherlock.tabs.ActionBarFragmentTabListener;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 /**
  * User: serso
  * Date: 9/25/12
@@ -187,7 +185,7 @@ public class CalculatorActivityHelperImpl extends AbstractCalculatorHelper imple
 			final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(activity);
 			final SharedPreferences.Editor editor = preferences.edit();
 			editor.putInt(getSavedTabPreferenceName(activity), selectedNavigationIndex);
-			editor.commit();
+			editor.apply();
 		}
 
 	}

android-app/src/main/java/org/solovyev/android/calculator/CalculatorDisplayMenuItem.java

@@ -24,15 +24,13 @@ package org.solovyev.android.calculator;
 
 import android.content.Context;
 import jscl.math.Generic;
-
-import javax.annotation.Nonnull;
-
-import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.android.calculator.plot.CalculatorPlotter;
 import org.solovyev.android.calculator.view.NumeralBaseConverterDialog;
 import org.solovyev.android.menu.LabeledMenuItem;
 
+import javax.annotation.Nonnull;
+
 /**
  * User: Solovyev_S
  * Date: 21.09.12
@@ -102,7 +100,7 @@ public enum CalculatorDisplayMenuItem implements LabeledMenuItem<CalculatorDispl
 		@Override
 		public void onClick(@Nonnull CalculatorDisplayViewState data, @Nonnull Context context) {
 			final Generic expression = data.getResult();
-			assert expression != null;
+			if (expression == null) throw new AssertionError();
 
 			final CalculatorPlotter plotter = Locator.getInstance().getPlotter();
 			plotter.plot(expression);

android-app/src/main/java/org/solovyev/android/calculator/CalculatorFragmentHelperImpl.java

@@ -33,6 +33,8 @@ import org.solovyev.android.checkout.*;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import java.util.Locale;
+
 import static java.util.Arrays.asList;
 
 /**
@@ -82,7 +84,7 @@ public class CalculatorFragmentHelperImpl extends AbstractCalculatorHelper imple
 			if (!isPane(fragment)) {
 				fragmentTitle.setVisibility(View.GONE);
 			} else {
-				fragmentTitle.setText(fragment.getString(titleResId).toUpperCase());
+				fragmentTitle.setText(fragment.getString(titleResId).toUpperCase(Locale.getDefault()));
 			}
 		}
 	}

android-app/src/main/java/org/solovyev/android/calculator/DigitButtonDragProcessor.java

@@ -23,15 +23,14 @@
 package org.solovyev.android.calculator;
 
 import android.view.MotionEvent;
-
-import javax.annotation.Nonnull;
-
 import org.solovyev.android.view.drag.DirectionDragButton;
 import org.solovyev.android.view.drag.DragButton;
 import org.solovyev.android.view.drag.DragDirection;
 import org.solovyev.android.view.drag.SimpleOnDragListener;
 import org.solovyev.common.math.Point2d;
 
+import javax.annotation.Nonnull;
+
 /**
  * User: serso
  * Date: 9/16/11
@@ -48,7 +47,7 @@ public class DigitButtonDragProcessor implements SimpleOnDragListener.DragProces
 
 	@Override
 	public boolean processDragEvent(@Nonnull DragDirection dragDirection, @Nonnull DragButton dragButton, @Nonnull Point2d startPoint2d, @Nonnull MotionEvent motionEvent) {
-		assert dragButton instanceof DirectionDragButton;
+		if (!(dragButton instanceof DirectionDragButton)) throw new AssertionError();
 		calculatorKeyboard.buttonPressed(((DirectionDragButton) dragButton).getText(dragDirection));
 		return true;
 	}

android-app/src/main/java/org/solovyev/android/calculator/about/CalculatorReleaseNotesFragment.java

@@ -78,7 +78,7 @@ public class CalculatorReleaseNotesFragment extends CalculatorFragment {
 			final String versionName = getVersionName(textHelper, versionCode);
 			String releaseNotesForVersion = textHelper.getText(makeReleaseNotesResourceId(versionCode));
 			if (!Strings.isEmpty(releaseNotesForVersion)) {
-				assert releaseNotesForVersion != null;
+				if (releaseNotesForVersion == null) throw new AssertionError();
 				if (!first) {
 					result.append("<br/><br/>");
 				} else {

android-app/src/main/java/org/solovyev/android/calculator/function/FunctionParamsView.java

@@ -22,7 +22,9 @@
 
 package org.solovyev.android.calculator.function;
 
+import android.annotation.TargetApi;
 import android.content.Context;
+import android.os.Build;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -31,12 +33,10 @@ import android.widget.EditText;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 import jscl.text.MutableInt;
+import org.solovyev.android.calculator.R;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-
-import org.solovyev.android.calculator.R;
-
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -59,6 +59,7 @@ public class FunctionParamsView extends LinearLayout {
 		super(context, attrs);
 	}
 
+	@TargetApi(Build.VERSION_CODES.HONEYCOMB)
 	public FunctionParamsView(Context context, AttributeSet attrs, int defStyle) {
 		super(context, attrs, defStyle);
 	}

android-app/src/main/java/org/solovyev/android/calculator/history/AbstractCalculatorHistoryFragment.java

@@ -245,7 +245,7 @@ public abstract class AbstractCalculatorHistoryFragment extends SherlockListFrag
 	}
 
 	public static boolean isAlreadySaved(@Nonnull CalculatorHistoryState historyState) {
-		assert !historyState.isSaved();
+		if (historyState.isSaved()) throw new AssertionError();
 
 		boolean result = false;
 		try {

android-app/src/main/java/org/solovyev/android/calculator/history/AndroidCalculatorHistory.java

@@ -70,7 +70,7 @@ public class AndroidCalculatorHistory implements CalculatorHistory {
 
 		editor.putString("org.solovyev.android.calculator.CalculatorModel_history", calculatorHistory.toXml());
 
-		editor.commit();
+		editor.apply();
 	}
 
 	public void clearSavedHistory() {

android-app/src/main/java/org/solovyev/android/calculator/math/edit/CalculatorVarsFragment.java

@@ -25,17 +25,11 @@ package org.solovyev.android.calculator.math.edit;
 import android.content.Context;
 import android.os.Bundle;
 import android.view.View;
-
 import com.actionbarsherlock.app.SherlockFragmentActivity;
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuInflater;
 import com.actionbarsherlock.view.MenuItem;
-
 import jscl.math.function.IConstant;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
 import org.solovyev.android.calculator.*;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.android.menu.AMenuItem;
@@ -44,6 +38,8 @@ import org.solovyev.common.JPredicate;
 import org.solovyev.common.collections.Collections;
 import org.solovyev.common.text.Strings;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -269,7 +265,7 @@ public class CalculatorVarsFragment extends AbstractMathEntityListFragment<ICons
 			public void onClick(@Nonnull IConstant data, @Nonnull Context context) {
 				final String text = data.getValue();
 				if (!Strings.isEmpty(text)) {
-					assert text != null;
+					if (text == null) throw new AssertionError();
 					Locator.getInstance().getClipboard().setText(text);
 				}
 			}
@@ -280,7 +276,7 @@ public class CalculatorVarsFragment extends AbstractMathEntityListFragment<ICons
 			public void onClick(@Nonnull IConstant data, @Nonnull Context context) {
 				final String text = Locator.getInstance().getEngine().getVarsRegistry().getDescription(data.getName());
 				if (!Strings.isEmpty(text)) {
-					assert text != null;
+					if (text == null) throw new AssertionError();
 					Locator.getInstance().getClipboard().setText(text);
 				}
 			}

android-app/src/main/java/org/solovyev/android/calculator/math/edit/VarEditDialogFragment.java

@@ -180,7 +180,7 @@ public class VarEditDialogFragment extends DialogFragment implements CalculatorE
 		final View.OnClickListener buttonOnClickListener = new View.OnClickListener() {
 			@Override
 			public void onClick(View view) {
-				assert view instanceof Button;
+				if (!(view instanceof Button)) throw new AssertionError();
 				editName.append(((Button) view).getText());
 			}
 		};

android-app/src/main/java/org/solovyev/android/calculator/math/edit/VarEditorSaver.java

@@ -28,10 +28,6 @@ import jscl.text.Identifier;
 import jscl.text.MutableInt;
 import jscl.text.ParseException;
 import jscl.text.Parser;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
 import org.solovyev.android.calculator.CalculatorMathRegistry;
 import org.solovyev.android.calculator.CalculatorVarsRegistry;
 import org.solovyev.android.calculator.Locator;
@@ -42,6 +38,9 @@ import org.solovyev.common.math.MathEntity;
 import org.solovyev.common.msg.MessageType;
 import org.solovyev.common.text.Strings;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 /**
  * User: serso
  * Date: 12/22/11
@@ -146,7 +145,7 @@ public class VarEditorSaver<T extends MathEntity> implements View.OnClickListene
 
 		if (!Strings.isEmpty(name)) {
 			try {
-				assert name != null;
+				if (name == null) throw new AssertionError();
 				Identifier.parser.parse(Parser.Parameters.newInstance(name, new MutableInt(0), Locator.getInstance().getEngine().getMathEngine0()), null);
 				result = true;
 			} catch (ParseException e) {

android-app/src/main/java/org/solovyev/android/calculator/model/AndroidMathEntityDao.java

@@ -81,7 +81,7 @@ public class AndroidMathEntityDao<T extends MathPersistenceEntity> implements Ma
 
 			editor.putString(preferenceString, sw.toString());
 
-			editor.commit();
+			editor.apply();
 		}
 	}
 

android-app/src/main/java/org/solovyev/android/calculator/onscreen/CalculatorOnscreenView.java

@@ -38,6 +38,7 @@ import org.solovyev.android.prefs.Preference;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.Locale;
 
 /**
  * User: serso
@@ -530,7 +531,7 @@ public class CalculatorOnscreenView {
 			if (value >= 0) {
 				return "+" + String.format("%.2f", value);
 			} else {
-				return String.format("%.2f", value);
+				return String.format(Locale.ENGLISH, "%.2f", value);
 			}
 		}
 	}

android-app/src/main/java/org/solovyev/android/calculator/plot/AbstractCalculatorPlotFragment.java

@@ -165,7 +165,7 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
 			case plot_data_changed:
 				final CalculatorEventHolder.Result result = this.lastEventHolder.apply(calculatorEventData);
 				if (result.isNewAfter()) {
-					assert data != null;
+					if (data == null) throw new AssertionError();
 					onNewPlotData((PlotData) data);
 				}
 				break;
@@ -191,7 +191,7 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
 					createGraphicalView(view, plotData);
 				}
 
-				assert activity != null;
+				if (activity == null) throw new AssertionError();
 				activity.invalidateOptionsMenu();
 			}
 		});

android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFragment.java

@@ -95,7 +95,7 @@ public class CalculatorPlotFragment extends AbstractCalculatorPlotFragment {
 	@Nonnull
 	@Override
 	protected Bitmap getScreehshot() {
-		assert this.graphView != null;
+		if (this.graphView == null) throw new AssertionError();
 		return this.graphView.captureScreenshot();
 	}
 

android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFunctionsActivity.java

@@ -23,13 +23,9 @@
 package org.solovyev.android.calculator.plot;
 
 import android.os.Bundle;
-
 import com.actionbarsherlock.app.SherlockFragmentActivity;
 import com.google.common.base.Function;
 import com.google.common.collect.Lists;
-
-import javax.annotation.Nullable;
-
 import org.solovyev.android.calculator.CalculatorFragmentType;
 import org.solovyev.android.calculator.CalculatorListFragment;
 import org.solovyev.android.calculator.Locator;
@@ -37,6 +33,7 @@ import org.solovyev.android.calculator.R;
 import org.solovyev.android.fragments.FragmentUtils;
 import org.solovyev.android.list.ListItemAdapter;
 
+import javax.annotation.Nullable;
 import java.util.List;
 
 /**
@@ -68,7 +65,7 @@ public class CalculatorPlotFunctionsActivity extends SherlockFragmentActivity {
 			final List<PlotFunctionListItem> items = Lists.transform(Locator.getInstance().getPlotter().getFunctions(), new Function<PlotFunction, PlotFunctionListItem>() {
 				@Override
 				public PlotFunctionListItem apply(@javax.annotation.Nullable PlotFunction input) {
-					assert input != null;
+					if (input == null) throw new AssertionError();
 					return new PlotFunctionListItem(input);
 				}
 			});

android-app/src/main/java/org/solovyev/android/calculator/widget/AbstractCalculatorWidgetProvider.java

@@ -22,6 +22,7 @@
 
 package org.solovyev.android.calculator.widget;
 
+import android.annotation.TargetApi;
 import android.app.PendingIntent;
 import android.appwidget.AppWidgetManager;
 import android.appwidget.AppWidgetProvider;
@@ -147,6 +148,13 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
 
 	private int getLayout(@Nonnull AppWidgetManager appWidgetManager, int appWidgetId, @Nonnull Resources resources) {
 		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
+			return getLayoutJellyBean(appWidgetManager, appWidgetId, resources);
+		}
+		return R.layout.widget_layout;
+	}
+
+	@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
+	private int getLayoutJellyBean(AppWidgetManager appWidgetManager, int appWidgetId, Resources resources) {
 		final Bundle options = appWidgetManager.getAppWidgetOptions(appWidgetId);
 
 		if (options != null) {
@@ -168,7 +176,6 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
 				}
 			}
 		}
-		}
 		return R.layout.widget_layout;
 	}
 

android-app/src/main/res/layout/display_error_message.xml

@@ -26,15 +26,13 @@
 			a:layout_width="fill_parent"
 			a:layout_height="fill_parent">
 
-	<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
+	<LinearLayout a:orientation="vertical"
-				  a:orientation="vertical"
+				  a:layout_width="match_parent"
-				  a:layout_width="fill_parent"
+				  a:layout_height="wrap_content"
-				  a:layout_height="fill_parent"
 				  a:scrollbars="vertical"
 				  a:scrollbarAlwaysDrawVerticalTrack="true">
 
-		<TextView xmlns:a="http://schemas.android.com/apk/res/android"
+		<TextView a:id="@+id/error_message_text_view"
-				  a:id="@+id/error_message_text_view"
 				  a:layout_height="fill_parent"
 				  a:layout_width="wrap_content"
 				  a:padding="6dp"

android-app/src/main/res/layout/drag_button_calibration.xml

@@ -78,6 +78,5 @@
 			a:text="@string/c_restart"
 			a:layout_width="wrap_content"
 			a:layout_height="wrap_content"
-			a:onClick="restartClickHandler"
 			a:layout_gravity="bottom"/>
 </LinearLayout>

android-app/src/main/res/layout/history_edit.xml

@@ -29,8 +29,8 @@
 	<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
 				  a:id="@+id/history_edit"
 				  a:orientation="vertical"
-				  a:layout_width="fill_parent"
+				  a:layout_width="match_parent"
-				  a:layout_height="fill_parent"
+				  a:layout_height="wrap_content"
 				  a:scrollbars="vertical"
 				  a:scrollbarAlwaysDrawVerticalTrack="true">
 

android-app/src/main/res/layout/matrix_edit_fragment.xml

@@ -74,7 +74,7 @@
 					<org.solovyev.android.calculator.matrix.MatrixView
 							a:id="@+id/matrix_layout"
 							a:layout_height="match_parent"
-							a:layout_width="match_parent"
+							a:layout_width="wrap_content"
 							a:minWidth="300dp"/>
 
 				</HorizontalScrollView>

android-app/src/main/res/values-large/arrays.xml

@@ -20,15 +20,15 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<resources>
+<resources xmlns:tools="http://schemas.android.com/tools">
 
-	<string-array name="p_layout_names">
+	<string-array name="p_layout_names" tools:ignore="InconsistentArrays">
 		<item>@string/p_layout_calculator</item>
 		<item>@string/p_layout_calculator_mobile</item>
 		<item>@string/p_layout_simple</item>
 		<item>@string/p_layout_simple_mobile</item>
 	</string-array>
-	<string-array name="p_layout_values" translatable="false">
+	<string-array name="p_layout_values" translatable="false" tools:ignore="InconsistentArrays">
 		<item>main_calculator</item>
 		<item>main_calculator_mobile</item>
 		<item>simple</item>

android-app/src/main/res/values/arrays.xml

@@ -20,7 +20,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<resources>
+<resources xmlns:tools="http://schemas.android.com/tools">
 	<string-array name="p_theme_names">
 		<item>@string/p_default_theme</item>
 		<item>@string/p_violet_theme</item>
@@ -55,11 +55,11 @@
 		<item>"∙"</item>
 	</string-array>
 
-	<string-array name="p_layout_names">
+	<string-array name="p_layout_names" tools:ignore="InconsistentArrays">
 		<item>@string/p_layout_calculator</item>
 		<item>@string/p_layout_simple</item>
 	</string-array>
-	<string-array name="p_layout_values" translatable="false">
+	<string-array name="p_layout_values" translatable="false" tools:ignore="InconsistentArrays">
 		<item>main_calculator</item>
 		<item>simple</item>
 	</string-array>

core/src/main/java/org/solovyev/android/calculator/CalculatorEditorImpl.java

@@ -120,7 +120,7 @@ public class CalculatorEditorImpl implements CalculatorEditor {
 	}
 
 	private void fireStateChangedEvent(boolean majorChanges, @Nonnull CalculatorEditorViewState oldViewState, @Nonnull CalculatorEditorViewState newViewState) {
-		assert Thread.holdsLock(viewLock);
+		if (!Thread.holdsLock(viewLock)) throw new AssertionError();
 
 		if (majorChanges) {
 			calculator.fireCalculatorEvent(editor_state_changed, newChangeEventData(oldViewState, newViewState));

core/src/main/java/org/solovyev/android/calculator/CalculatorKeyboardImpl.java

@@ -46,7 +46,7 @@ public class CalculatorKeyboardImpl implements CalculatorKeyboard {
 	public void buttonPressed(@Nullable final String text) {
 
 		if (!Strings.isEmpty(text)) {
-			assert text != null;
+			if (text == null) throw new AssertionError();
 
 			// process special buttons
 			boolean processed = processSpecialButtons(text);

core/src/main/java/org/solovyev/android/calculator/ToJsclTextProcessor.java

@@ -24,15 +24,13 @@ package org.solovyev.android.calculator;
 
 import jscl.math.function.Function;
 import jscl.math.function.IConstant;
-
-import javax.annotation.Nonnull;
-
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.android.calculator.text.TextProcessor;
 import org.solovyev.common.collections.Collections;
 import org.solovyev.common.msg.MessageType;
 import org.solovyev.common.search.StartsWithFinder;
 
+import javax.annotation.Nonnull;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -135,7 +133,7 @@ public class ToJsclTextProcessor implements TextProcessor<PreparedExpression, St
 								offset = varName.length();
 							} else {
 								final String value = var.getValue();
-								assert value != null;
+								if (value == null) throw new AssertionError();
 
 								if (var.getDoubleValue() != null) {
 									//result.append(value);

core/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotterImpl.java

@@ -82,7 +82,7 @@ public class CalculatorPlotterImpl implements CalculatorPlotter {
 	public boolean addFunction(@Nonnull Generic expression) {
 		final List<Constant> variables = new ArrayList<Constant>(CalculatorUtils.getNotSystemConstants(expression));
 
-		assert variables.size() <= 2;
+		if (variables.size() > 2) throw new AssertionError();
 
 		final Constant xVariable;
 		if (variables.size() > 0) {
@@ -316,7 +316,7 @@ public class CalculatorPlotterImpl implements CalculatorPlotter {
 
 	// NOTE: this method must be called from synchronized block
 	private void onFunctionsChanged() {
-		assert Thread.holdsLock(functions);
+		if (!Thread.holdsLock(functions)) throw new AssertionError();
 
 		int maxArity = 0;
 		for (PlotFunction function : functions) {

core/src/main/java/org/solovyev/android/calculator/plot/MapPlotResourceManager.java

@@ -69,7 +69,7 @@ public class MapPlotResourceManager implements PlotResourceManager {
 	}
 
 	private void addLineDef(@Nonnull final PlotLineDef toBeAdded) {
-		assert Thread.holdsLock(this);
+		if (!Thread.holdsLock(this)) throw new AssertionError();
 
 		List<PlotLineDef> registeredLineDefs = registeredLineDefsMap.get(toBeAdded);
 		if (registeredLineDefs == null) {
@@ -94,7 +94,7 @@ public class MapPlotResourceManager implements PlotResourceManager {
 	}
 
 	private void removeLineDef(@Nonnull final PlotLineDef toBeRemoved) {
-		assert Thread.holdsLock(this);
+		if (!Thread.holdsLock(this)) throw new AssertionError();
 
 		List<PlotLineDef> registeredLineDefs = registeredLineDefsMap.get(toBeRemoved);