style(gui): reformat code and fix some warnings

jadx-gui/src/main/java/jadx/gui/JadxWrapper.java

@@ -67,7 +67,6 @@ public class JadxWrapper {
 
 	/**
 	 * Get the complete list of classes
-	 * @return
 	 */
 	public List<JavaClass> getClasses() {
 		return decompiler.getClasses();
@@ -75,20 +74,21 @@ public class JadxWrapper {
 
 	/**
 	 * Get all classes that are not excluded by the excluded packages settings
-	 * @return
 	 */
 	public List<JavaClass> getIncludedClasses() {
 		List<JavaClass> classList = decompiler.getClasses();
 		String excludedPackages = settings.getExcludedPackages().trim();
-		if (excludedPackages.length() == 0)
+		if (excludedPackages.length() == 0) {
 			return classList;
+		}
 		String[] excluded = excludedPackages.split("[ ]+");
 
 		return classList.stream().filter(cls -> {
 			for (String exclude : excluded) {
-				if (cls.getFullName().startsWith(exclude))
+				if (cls.getFullName().startsWith(exclude)) {
 					return false;
 				}
+			}
 			return true;
 		}).collect(Collectors.toList());
 	}

jadx-gui/src/main/java/jadx/gui/jobs/BackgroundWorker.java

@@ -3,12 +3,12 @@ package jadx.gui.jobs;
 import javax.swing.*;
 import java.util.concurrent.Future;
 
-import jadx.gui.utils.NLS;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import jadx.gui.ui.ProgressPanel;
 import jadx.gui.utils.CacheObject;
+import jadx.gui.utils.NLS;
 import jadx.gui.utils.Utils;
 import jadx.gui.utils.search.TextSearchIndex;
 
@@ -27,12 +27,7 @@ public class BackgroundWorker extends SwingWorker<Void, Void> {
 		if (isDone()) {
 			return;
 		}
-		SwingUtilities.invokeLater(new Runnable() {
-			@Override
-			public void run() {
-				progressPane.setVisible(true);
-			}
-		});
+		SwingUtilities.invokeLater(() -> progressPane.setVisible(true));
 		addPropertyChangeListener(progressPane);
 		execute();
 	}
@@ -46,7 +41,7 @@ public class BackgroundWorker extends SwingWorker<Void, Void> {
 	}
 
 	@Override
-	protected Void doInBackground() throws Exception {
+	protected Void doInBackground() {
 		try {
 			System.gc();
 			LOG.debug("Memory usage: Before decompile: {}", Utils.memoryInfo());

jadx-gui/src/main/java/jadx/gui/jobs/DecompileJob.java

@@ -11,12 +11,7 @@ public class DecompileJob extends BackgroundJob {
 
 	protected void runJob() {
 		for (final JavaClass cls : wrapper.getIncludedClasses()) {
-			addTask(new Runnable() {
-				@Override
-				public void run() {
-					cls.decompile();
-				}
-			});
+			addTask(cls::decompile);
 		}
 	}
 

jadx-gui/src/main/java/jadx/gui/settings/JadxSettings.java

@@ -150,7 +150,6 @@ public class JadxSettings extends JadxCLIArgs {
 		return true;
 	}
 
-
 	public boolean isShowHeapUsageBar() {
 		return showHeapUsageBar;
 	}

jadx-gui/src/main/java/jadx/gui/settings/JadxSettingsAdapter.java

@@ -21,7 +21,7 @@ public class JadxSettingsAdapter {
 
 	private static final Preferences PREFS = Preferences.userNodeForPackage(JadxGUI.class);
 
-	private static ExclusionStrategy EXCLUDE_FIELDS = new ExclusionStrategy() {
+	private static final ExclusionStrategy EXCLUDE_FIELDS = new ExclusionStrategy() {
 		@Override
 		public boolean shouldSkipField(FieldAttributes f) {
 			return JadxSettings.SKIP_FIELDS.contains(f.getName())

jadx-gui/src/main/java/jadx/gui/settings/JadxSettingsWindow.java

 package jadx.gui.settings;
 
 import javax.swing.*;
-import javax.swing.event.DocumentEvent;
-import javax.swing.event.DocumentListener;
 import java.awt.*;
 import java.awt.event.ItemEvent;
 import java.awt.event.MouseAdapter;
@@ -245,11 +243,11 @@ public class JadxSettingsWindow extends JDialog {
 		});
 
 		JButton editExcludedPackages = new JButton(NLS.str("preferences.excludedPackages.button"));
-		editExcludedPackages.addActionListener( event -> {
+		editExcludedPackages.addActionListener(event -> {
 
 			String result = JOptionPane.showInputDialog(this, NLS.str("preferences.excludedPackages.editDialog"),
 					settings.getExcludedPackages());
-			if (result !=null) {
+			if (result != null) {
 				settings.setExcludedPackages(result);
 			}
 		});

jadx-gui/src/main/java/jadx/gui/treemodel/ApkSignature.java

 package jadx.gui.treemodel;
 
+import javax.swing.*;
+import java.io.File;
+import java.security.cert.Certificate;
+import java.util.List;
+import java.util.stream.Collectors;
+
 import com.android.apksig.ApkVerifier;
-import jadx.api.ResourceType;
-import jadx.gui.JadxWrapper;
-import jadx.gui.utils.CertificateManager;
-import jadx.gui.utils.NLS;
-import jadx.gui.utils.Utils;
 import org.apache.commons.lang3.exception.ExceptionUtils;
 import org.apache.commons.text.StringEscapeUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.swing.*;
-import java.io.File;
-import java.security.cert.Certificate;
-import java.util.List;
-import java.util.stream.Collectors;
+import jadx.gui.JadxWrapper;
+import jadx.gui.utils.CertificateManager;
+import jadx.gui.utils.NLS;
+import jadx.gui.utils.Utils;
 
 public class ApkSignature extends JNode {
+	private static final long serialVersionUID = -9121321926113143407L;
+
+	private static final Logger LOG = LoggerFactory.getLogger(ApkSignature.class);
 
-	private static final Logger log = LoggerFactory.getLogger(ApkSignature.class);
 	private static final ImageIcon CERTIFICATE_ICON = Utils.openIcon("certificate_obj");
 
 	private final transient File openFile;
-	private String content = null;
+	private String content;
 
 	public static ApkSignature getApkSignature(JadxWrapper wrapper) {
 		// Only show the ApkSignature node if an AndroidManifest.xml is present.
 		// Without a manifest the Google ApkVerifier refuses to work.
-		if (!wrapper.getResources().stream().anyMatch(r -> "AndroidManifest.xml".equals(r.getName()))) {
+		if (wrapper.getResources().stream().noneMatch(r -> "AndroidManifest.xml".equals(r.getName()))) {
 			return null;
 		}
 		File openFile = wrapper.getOpenFile();
@@ -56,8 +58,9 @@ public class ApkSignature extends JNode {
 
 	@Override
 	public String getContent() {
-		if (content != null)
+		if (content != null) {
 			return this.content;
+		}
 		ApkVerifier verifier = new ApkVerifier.Builder(openFile).build();
 		try {
 			ApkVerifier.Result result = verifier.verify();
@@ -80,7 +83,7 @@ public class ApkSignature extends JNode {
 			writeIssues(builder, err, result.getErrors());
 			writeIssues(builder, warn, result.getWarnings());
 
-			if (result.getV1SchemeSigners().size() > 0) {
+			if (!result.getV1SchemeSigners().isEmpty()) {
 				builder.append("<h2>");
 				builder.escape(String.format(result.isVerifiedUsingV1Scheme() ? sigSucc : sigFail, 1));
 				builder.append("</h2>\n");
@@ -101,7 +104,7 @@ public class ApkSignature extends JNode {
 				}
 				builder.append("</blockquote>");
 			}
-			if (result.getV2SchemeSigners().size() > 0) {
+			if (!result.getV2SchemeSigners().isEmpty()) {
 				builder.append("<h2>");
 				builder.escape(String.format(result.isVerifiedUsingV2Scheme() ? sigSucc : sigFail, 2));
 				builder.append("</h2>\n");
@@ -121,7 +124,7 @@ public class ApkSignature extends JNode {
 			}
 			this.content = builder.toString();
 		} catch (Exception e) {
-			log.error(e.getMessage(), e);
+			LOG.error(e.getMessage(), e);
 			StringEscapeUtils.Builder builder = StringEscapeUtils.builder(StringEscapeUtils.ESCAPE_HTML4);
 			builder.append("<h1>");
 			builder.escape(NLS.str("apkSignature.exception"));
@@ -147,7 +150,7 @@ public class ApkSignature extends JNode {
 	}
 
 	private void writeIssues(StringEscapeUtils.Builder builder, String issueType, List<ApkVerifier.IssueWithParams> issueList) {
-		if (issueList.size() > 0) {
+		if (!issueList.isEmpty()) {
 			builder.append("<h3>");
 			builder.escape(issueType);
 			builder.append("</h3>");
@@ -155,7 +158,7 @@ public class ApkSignature extends JNode {
 			// Unprotected Zip entry issues are very common, handle them separately
 			List<ApkVerifier.IssueWithParams> unprotIssues = issueList.stream().filter(i ->
 					i.getIssue() == ApkVerifier.Issue.JAR_SIG_UNPROTECTED_ZIP_ENTRY).collect(Collectors.toList());
-			if (unprotIssues.size() > 0) {
+			if (!unprotIssues.isEmpty()) {
 				builder.append("<h4>");
 				builder.escape(NLS.str("apkSignature.unprotectedEntry"));
 				builder.append("</h4><blockquote>");
@@ -167,7 +170,7 @@ public class ApkSignature extends JNode {
 			}
 			List<ApkVerifier.IssueWithParams> remainingIssues = issueList.stream().filter(i ->
 					i.getIssue() != ApkVerifier.Issue.JAR_SIG_UNPROTECTED_ZIP_ENTRY).collect(Collectors.toList());
-			if (remainingIssues.size() > 0) {
+			if (!remainingIssues.isEmpty()) {
 				builder.append("<pre>\n");
 				for (ApkVerifier.IssueWithParams issue : remainingIssues) {
 					builder.escape(issue.toString());
@@ -177,8 +180,5 @@ public class ApkSignature extends JNode {
 			}
 			builder.append("</blockquote>");
 		}
-
 	}
-
-
 }

jadx-gui/src/main/java/jadx/gui/treemodel/JSources.java

@@ -85,7 +85,7 @@ public class JSources extends JNode {
 			}
 		}
 		// use identity set for collect inner packages
-		Set<JPackage> innerPackages = Collections.newSetFromMap(new IdentityHashMap<JPackage, Boolean>());
+		Set<JPackage> innerPackages = Collections.newSetFromMap(new IdentityHashMap<>());
 		for (JPackage pkg : pkgMap.values()) {
 			innerPackages.addAll(pkg.getInnerPackages());
 		}

jadx-gui/src/main/java/jadx/gui/ui/AboutDialog.java

@@ -2,8 +2,6 @@ package jadx.gui.ui;
 
 import javax.swing.*;
 import java.awt.*;
-import java.awt.event.ActionEvent;
-import java.awt.event.ActionListener;
 
 import jadx.api.JadxDecompiler;
 import jadx.gui.utils.NLS;
@@ -42,11 +40,7 @@ class AboutDialog extends JDialog {
 		textPane.add(Box.createRigidArea(new Dimension(0, 20)));
 
 		JButton close = new JButton(NLS.str("tabs.close"));
-		close.addActionListener(new ActionListener() {
-			public void actionPerformed(ActionEvent event) {
-				dispose();
-			}
-		});
+		close.addActionListener(event -> dispose());
 		close.setAlignmentX(0.5f);
 
 		Container contentPane = getContentPane();

jadx-gui/src/main/java/jadx/gui/ui/CommonSearchDialog.java

@@ -33,14 +33,14 @@ import jadx.gui.jobs.DecompileJob;
 import jadx.gui.treemodel.JNode;
 import jadx.gui.ui.codearea.CodeArea;
 import jadx.gui.utils.CacheObject;
-import jadx.gui.utils.NLS;
 import jadx.gui.utils.JumpPosition;
+import jadx.gui.utils.NLS;
 import jadx.gui.utils.search.TextSearchIndex;
 
 public abstract class CommonSearchDialog extends JDialog {
+	private static final long serialVersionUID = 8939332306115370276L;
 
 	private static final Logger LOG = LoggerFactory.getLogger(CommonSearchDialog.class);
-	private static final long serialVersionUID = 8939332306115370276L;
 
 	public static final int RESULTS_PER_PAGE = 100;
 
@@ -399,7 +399,7 @@ public abstract class CommonSearchDialog extends JDialog {
 		private final JLabel emptyLabel = new JLabel();
 		private final Color codeSelectedColor;
 		private final Color codeBackground;
-		private Map<Integer, Component> componentCache = new HashMap<>();
+		private final Map<Integer, Component> componentCache = new HashMap<>();
 
 		public ResultsTableCellRenderer() {
 			RSyntaxTextArea area = CodeArea.getDefaultArea(mainWindow);

jadx-gui/src/main/java/jadx/gui/ui/HeapUsageBar.java

 package jadx.gui.ui;
 
-import jadx.gui.utils.NLS;
-import jadx.gui.utils.Utils;
-
 import javax.swing.*;
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 
-public class HeapUsageBar extends JProgressBar implements ActionListener {
-
-	private static final double TWO_TO_20 = 1048576d; // 1024 * 1024
-
-	private final Color GREEN = new Color(0, 180, 0);
-	private final Color RED = new Color(200, 0, 0);
+import jadx.gui.utils.NLS;
+import jadx.gui.utils.Utils;
 
-	private final Runtime r;
+public class HeapUsageBar extends JProgressBar implements ActionListener {
+	private static final long serialVersionUID = -8739563124249884967L;
 
-	private String maxHeapStr;
+	private static final double TWO_TO_20 = 1048576d;
 
-	private final Timer timer;
+	private static final Color GREEN = new Color(0, 180, 0);
+	private static final Color RED = new Color(200, 0, 0);
 
-	private final double maxGB;
+	private final transient Runtime runtime = Runtime.getRuntime();
+	private final transient Timer timer;
 
 	private final String textFormat;
+	private final double maxGB;
 
 	public HeapUsageBar() {
-		super();
-		textFormat = NLS.str("heapUsage.text");
-		r = Runtime.getRuntime();
+		this.textFormat = NLS.str("heapUsage.text");
 		setBorderPainted(false);
 		setStringPainted(true);
 		setValue(10);
-		int maxKB = (int) (r.maxMemory() / 1024);
+		int maxKB = (int) (runtime.maxMemory() / 1024);
 		setMaximum(maxKB);
 		maxGB = maxKB / TWO_TO_20;
 		update();
@@ -40,12 +35,12 @@ public class HeapUsageBar extends JProgressBar implements ActionListener {
 	}
 
 	public void update() {
-		long used = r.totalMemory() - r.freeMemory();
+		long used = runtime.totalMemory() - runtime.freeMemory();
 		int usedKB = (int) (used / 1024);
 		setValue(usedKB);
 		setString(String.format(textFormat, (usedKB / TWO_TO_20), maxGB));
 
-		if ((used + Utils.MIN_FREE_MEMORY) > r.maxMemory()) {
+		if ((used + Utils.MIN_FREE_MEMORY) > runtime.maxMemory()) {
 			setForeground(RED);
 		} else {
 			setForeground(GREEN);

jadx-gui/src/main/java/jadx/gui/ui/HtmlPanel.java

 package jadx.gui.ui;
 
-import jadx.gui.settings.JadxSettings;
-import jadx.gui.treemodel.JNode;
-import jadx.gui.ui.codearea.CodeArea;
-import org.fife.ui.rsyntaxtextarea.RSyntaxTextArea;
-
 import javax.swing.*;
-import javax.swing.event.DocumentEvent;
-import javax.swing.event.DocumentListener;
-import javax.swing.plaf.PanelUI;
 import java.awt.*;
-import java.awt.event.KeyEvent;
-import java.awt.event.KeyListener;
+
+import jadx.gui.settings.JadxSettings;
+import jadx.gui.treemodel.JNode;
 
 public final class HtmlPanel extends ContentPanel {
 	private static final long serialVersionUID = -6251262855835426245L;
@@ -36,14 +29,14 @@ public final class HtmlPanel extends ContentPanel {
 		textArea.setFont(settings.getFont());
 	}
 
-	private static class JHtmlPane extends JEditorPane {
-
-		boolean antiAliasingEnabled;
+	private static final class JHtmlPane extends JEditorPane {
+		private static final long serialVersionUID = 6886040384052136157L;
 
 		public JHtmlPane() {
 			setContentType("text/html");
 		}
 
+		@Override
 		public void paint(Graphics g) {
 			Graphics2D g2d = (Graphics2D) g.create();
 			try {
@@ -53,6 +46,5 @@ public final class HtmlPanel extends ContentPanel {
 				g2d.dispose();
 			}
 		}
-
 	}
 }

jadx-gui/src/main/java/jadx/gui/ui/MainDropTarget.java

@@ -59,7 +59,7 @@ public class MainDropTarget implements DropTargetListener {
 		try {
 			Transferable transferable = dtde.getTransferable();
 			List<File> transferData = (List<File>) transferable.getTransferData(DataFlavor.javaFileListFlavor);
-			if (transferData != null && transferData.size() > 0) {
+			if (!transferData.isEmpty()) {
 				dtde.dropComplete(true);
 				// load first file
 				mainWindow.openFile(transferData.get(0));

jadx-gui/src/main/java/jadx/gui/ui/MainWindow.java

@@ -9,7 +9,6 @@ import javax.swing.filechooser.FileNameExtensionFilter;
 import javax.swing.tree.DefaultMutableTreeNode;
 import javax.swing.tree.DefaultTreeCellRenderer;
 import javax.swing.tree.DefaultTreeModel;
-import javax.swing.tree.ExpandVetoException;
 import javax.swing.tree.TreeNode;
 import javax.swing.tree.TreePath;
 import javax.swing.tree.TreeSelectionModel;
@@ -28,7 +27,6 @@ import java.util.Arrays;
 import java.util.Timer;
 import java.util.TimerTask;
 
-import jadx.gui.treemodel.*;
 import org.fife.ui.rsyntaxtextarea.Theme;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -40,13 +38,20 @@ import jadx.gui.jobs.DecompileJob;
 import jadx.gui.jobs.IndexJob;
 import jadx.gui.settings.JadxSettings;
 import jadx.gui.settings.JadxSettingsWindow;
+import jadx.gui.treemodel.ApkSignature;
+import jadx.gui.treemodel.JCertificate;
+import jadx.gui.treemodel.JClass;
+import jadx.gui.treemodel.JLoadableNode;
+import jadx.gui.treemodel.JNode;
+import jadx.gui.treemodel.JResource;
+import jadx.gui.treemodel.JRoot;
 import jadx.gui.update.JadxUpdate;
 import jadx.gui.update.JadxUpdate.IUpdateCallback;
 import jadx.gui.update.data.Release;
 import jadx.gui.utils.CacheObject;
+import jadx.gui.utils.JumpPosition;
 import jadx.gui.utils.Link;
 import jadx.gui.utils.NLS;
-import jadx.gui.utils.JumpPosition;
 import jadx.gui.utils.Utils;
 
 import static javax.swing.KeyStroke.getKeyStroke;
@@ -90,7 +95,6 @@ public class MainWindow extends JFrame {
 	private boolean isFlattenPackage;
 	private JToggleButton flatPkgButton;
 	private JCheckBoxMenuItem flatPkgMenuItem;
-	private JCheckBoxMenuItem heapUsageBarMenuItem;
 
 	private JToggleButton deobfToggleBtn;
 	private JCheckBoxMenuItem deobfMenuItem;
@@ -382,7 +386,7 @@ public class MainWindow extends JFrame {
 		flatPkgMenuItem = new JCheckBoxMenuItem(NLS.str("menu.flatten"), ICON_FLAT_PKG);
 		flatPkgMenuItem.setState(isFlattenPackage);
 
-		heapUsageBarMenuItem = new JCheckBoxMenuItem(NLS.str("menu.heapUsageBar"));
+		JCheckBoxMenuItem heapUsageBarMenuItem = new JCheckBoxMenuItem(NLS.str("menu.heapUsageBar"));
 		heapUsageBarMenuItem.setState(settings.isShowHeapUsageBar());
 		heapUsageBarMenuItem.addActionListener(event -> {
 			settings.setShowHeapUsageBar(!settings.isShowHeapUsageBar());
@@ -589,7 +593,7 @@ public class MainWindow extends JFrame {
 		});
 		tree.addTreeWillExpandListener(new TreeWillExpandListener() {
 			@Override
-			public void treeWillExpand(TreeExpansionEvent event) throws ExpandVetoException {
+			public void treeWillExpand(TreeExpansionEvent event) {
 				TreePath path = event.getPath();
 				Object node = path.getLastPathComponent();
 				if (node instanceof JLoadableNode) {
@@ -598,7 +602,8 @@ public class MainWindow extends JFrame {
 			}
 
 			@Override
-			public void treeWillCollapse(TreeExpansionEvent event) throws ExpandVetoException {
+			public void treeWillCollapse(TreeExpansionEvent event) {
+				// ignore
 			}
 		});
 

jadx-gui/src/main/java/jadx/gui/ui/TabbedPane.java

 package jadx.gui.ui;
 
+import javax.swing.*;
+import javax.swing.plaf.basic.BasicButtonUI;
+import javax.swing.text.BadLocationException;
+import java.awt.*;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import jadx.api.ResourceFile;
 import jadx.api.ResourceType;
 import jadx.gui.treemodel.ApkSignature;
@@ -13,29 +28,6 @@ import jadx.gui.utils.JumpManager;
 import jadx.gui.utils.JumpPosition;
 import jadx.gui.utils.NLS;
 import jadx.gui.utils.Utils;
-import org.jetbrains.annotations.Nullable;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import javax.swing.BorderFactory;
-import javax.swing.ImageIcon;
-import javax.swing.JButton;
-import javax.swing.JLabel;
-import javax.swing.JMenuItem;
-import javax.swing.JPanel;
-import javax.swing.JPopupMenu;
-import javax.swing.JTabbedPane;
-import javax.swing.SwingUtilities;
-import javax.swing.plaf.basic.BasicButtonUI;
-import javax.swing.text.BadLocationException;
-import java.awt.Component;
-import java.awt.FlowLayout;
-import java.awt.event.MouseAdapter;
-import java.awt.event.MouseEvent;
-import java.util.ArrayList;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
 
 public class TabbedPane extends JTabbedPane {
 

jadx-gui/src/main/java/jadx/gui/ui/codearea/LineNumbers.java

@@ -32,16 +32,16 @@ public class LineNumbers extends JPanel implements CaretListener {
 	private static final int NUM_HEIGHT = Integer.MAX_VALUE - 1000000;
 	private static final Map<?, ?> DESKTOP_HINTS = (Map<?, ?>) Toolkit.getDefaultToolkit().getDesktopProperty("awt.font.desktophints");
 
-	private CodeArea codeArea;
+	private final CodeArea codeArea;
 	private boolean useSourceLines = true;
 
 	private int lastDigits;
 	private int lastLine;
 	private Map<String, FontMetrics> fonts;
 
-	private transient final Color numberColor;
-	private transient final Color currentColor;
-	private transient final Border border;
+	private final transient Color numberColor;
+	private final transient Color currentColor;
+	private final transient Border border;
 
 	public LineNumbers(CodeArea component) {
 		this.codeArea = component;
@@ -199,12 +199,10 @@ public class LineNumbers extends JPanel implements CaretListener {
 				String fontFamily = (String) as.getAttribute(StyleConstants.FontFamily);
 				Integer fontSize = (Integer) as.getAttribute(StyleConstants.FontSize);
 				String key = fontFamily + fontSize;
-				FontMetrics fm = fonts.get(key);
-				if (fm == null) {
+				FontMetrics fm = fonts.computeIfAbsent(key, k -> {
 					Font font = new Font(fontFamily, Font.PLAIN, fontSize);
-					fm = codeArea.getFontMetrics(font);
-					fonts.put(key, fm);
-				}
+					return codeArea.getFontMetrics(font);
+				});
 				descent = Math.max(descent, fm.getDescent());
 			}
 		}

jadx-gui/src/main/java/jadx/gui/update/JadxUpdate.java

@@ -6,9 +6,8 @@ import java.io.Reader;
 import java.lang.reflect.Type;
 import java.net.HttpURLConnection;
 import java.net.URL;
-import java.util.Collections;
+import java.nio.charset.StandardCharsets;
 import java.util.Comparator;
-import java.util.Iterator;
 import java.util.List;
 
 import com.google.gson.Gson;
@@ -32,12 +31,8 @@ public class JadxUpdate {
 	private static final Type RELEASES_LIST_TYPE = new TypeToken<List<Release>>() {
 	}.getType();
 
-	private static final Comparator<Release> RELEASE_COMPARATOR = new Comparator<Release>() {
-		@Override
-		public int compare(Release o1, Release o2) {
-			return VersionComparator.checkAndCompare(o1.getName(), o2.getName());
-		}
-	};
+	private static final Comparator<Release> RELEASE_COMPARATOR = (o1, o2) ->
+			VersionComparator.checkAndCompare(o1.getName(), o2.getName());
 
 	public interface IUpdateCallback {
 		void onUpdate(Release r);
@@ -47,9 +42,7 @@ public class JadxUpdate {
 	}
 
 	public static void check(final IUpdateCallback callback) {
-		Runnable run = new Runnable() {
-			@Override
-			public void run() {
+		Runnable run = () -> {
 			try {
 				Release release = checkForNewRelease();
 				if (release != null) {
@@ -58,7 +51,6 @@ public class JadxUpdate {
 			} catch (Exception e) {
 				LOG.debug("Jadx update error", e);
 			}
-			}
 		};
 		Thread thread = new Thread(run);
 		thread.setName("Jadx update thread");
@@ -77,17 +69,11 @@ public class JadxUpdate {
 		if (list == null) {
 			return null;
 		}
-		for (Iterator<Release> it = list.iterator(); it.hasNext(); ) {
-			Release release = it.next();
-			if (release.getName().equalsIgnoreCase(version)
-					|| release.isPreRelease()) {
-				it.remove();
-			}
-		}
+		list.removeIf(release -> release.getName().equalsIgnoreCase(version) || release.isPreRelease());
 		if (list.isEmpty()) {
 			return null;
 		}
-		Collections.sort(list, RELEASE_COMPARATOR);
+		list.sort(RELEASE_COMPARATOR);
 		Release latest = list.get(list.size() - 1);
 		if (VersionComparator.checkAndCompare(version, latest.getName()) >= 0) {
 			return null;
@@ -101,7 +87,7 @@ public class JadxUpdate {
 		HttpURLConnection con = (HttpURLConnection) obj.openConnection();
 		con.setRequestMethod("GET");
 		if (con.getResponseCode() == 200) {
-			Reader reader = new InputStreamReader(con.getInputStream(), "UTF-8");
+			Reader reader = new InputStreamReader(con.getInputStream(), StandardCharsets.UTF_8);
 			return GSON.fromJson(reader, type);
 		}
 		return null;

jadx-gui/src/main/java/jadx/gui/utils/CertificateManager.java

@@ -21,8 +21,8 @@ public class CertificateManager {
 	private static final Logger LOG = LoggerFactory.getLogger(CertificateManager.class);
 	private static final String CERTIFICATE_TYPE_NAME = "X.509";
 
+	private final Certificate cert;
 	private X509Certificate x509cert;
-	private Certificate cert;
 
 	public static String decode(InputStream in) {
 		StringBuilder strBuild = new StringBuilder();

jadx-gui/src/main/java/jadx/gui/utils/CodeLinesInfo.java

@@ -9,7 +9,7 @@ import jadx.api.JavaMethod;
 import jadx.api.JavaNode;
 
 public class CodeLinesInfo {
-	private NavigableMap<Integer, JavaNode> map = new TreeMap<>();
+	private final NavigableMap<Integer, JavaNode> map = new TreeMap<>();
 
 	public CodeLinesInfo(JavaClass cls) {
 		addClass(cls);

jadx-gui/src/main/java/jadx/gui/utils/CodeUsageInfo.java

@@ -2,7 +2,6 @@ package jadx.gui.utils;
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;

jadx-gui/src/main/java/jadx/gui/utils/JumpManager.java

@@ -5,7 +5,7 @@ import java.util.List;
 
 public class JumpManager {
 
-	private List<JumpPosition> list = new ArrayList<>();
+	private final List<JumpPosition> list = new ArrayList<>();
 	private int currentPos = 0;
 
 	public void addPosition(JumpPosition pos) {

jadx-gui/src/main/java/jadx/gui/utils/LangLocale.java

@@ -3,7 +3,7 @@ package jadx.gui.utils;
 import java.util.Locale;
 
 public class LangLocale {
-	private Locale locale;
+	private final Locale locale;
 
 	public LangLocale(Locale locale) {
 		this.locale = locale;

jadx-gui/src/main/java/jadx/gui/utils/Link.java

@@ -16,7 +16,7 @@ public class Link extends JLabel implements MouseListener {
 
 	private static final Logger LOG = LoggerFactory.getLogger(Link.class);
 
-	private String url;
+	private final String url;
 
 	public Link(String text, String url) {
 		super(text);

jadx-gui/src/main/java/jadx/gui/utils/NLS.java

@@ -4,24 +4,29 @@ import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.net.URL;
-import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
-import java.util.*;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.MissingResourceException;
+import java.util.PropertyResourceBundle;
+import java.util.ResourceBundle;
+import java.util.Vector;
 
-import org.jetbrains.annotations.NotNull;
+import jadx.core.utils.exceptions.JadxRuntimeException;
 
 public class NLS {
 
-	private static Vector<LangLocale> i18nLocales = new Vector<>();
+	private static final Vector<LangLocale> i18nLocales = new Vector<>();
 
-	private static Map<LangLocale, ResourceBundle> i18nMessagesMap = new HashMap<>();
+	private static final Map<LangLocale, ResourceBundle> i18nMessagesMap = new HashMap<>();
+
+	private static final ResourceBundle fallbackMessagesMap;
+	private static final LangLocale localLocale;
 
 	// Use these two fields to avoid invoking Map.get() method twice.
 	private static ResourceBundle localizedMessagesMap;
-	private static ResourceBundle fallbackMessagesMap;
-
 	private static LangLocale currentLocale;
-	private static LangLocale localLocale;
 
 	static {
 		localLocale = new LangLocale(Locale.getDefault());
@@ -45,10 +50,13 @@ public class NLS {
 		ClassLoader classLoader = ClassLoader.getSystemClassLoader();
 		String resName = String.format("i18n/Messages_%s.properties", locale.get());
 		URL bundleUrl = classLoader.getResource(resName);
+		if (bundleUrl == null) {
+			throw new JadxRuntimeException("Locale resource not found: " + resName);
+		}
 		try (Reader reader = new InputStreamReader(bundleUrl.openStream(), StandardCharsets.UTF_8)) {
 			bundle = new PropertyResourceBundle(reader);
 		} catch (IOException e) {
-			throw new RuntimeException("Failed to load " + resName, e);
+			throw new JadxRuntimeException("Failed to load " + resName, e);
 		}
 		i18nMessagesMap.put(locale, bundle);
 	}
@@ -66,7 +74,8 @@ public class NLS {
 		if (bundle != null) {
 			try {
 				return bundle.getString(key);
-			} catch (MissingResourceException e) {
+			} catch (MissingResourceException ignored) {
+				// use fallback string
 			}
 		}
 		return fallbackMessagesMap.getString(key); // definitely exists

jadx-gui/src/main/java/jadx/gui/utils/Utils.java

@@ -30,7 +30,7 @@ public class Utils {
 	 * The minimum about of memory in bytes we are trying to keep free, otherwise the application may run out of heap
 	 * which ends up in a Java garbage collector running "amok" (CPU utilization 100% for each core and the UI is
 	 * not responsive).
-	 *
+	 * <p>
 	 * We can calculate and store this value here as the maximum heap is fixed for each JVM instance
 	 * and can't be changed at runtime.
 	 */
@@ -123,8 +123,7 @@ public class Utils {
 	public static long calculateMinFreeMemory() {
 		Runtime runtime = Runtime.getRuntime();
 		long minFree = (long) (runtime.maxMemory() * 0.2);
-		minFree = Math.min(minFree, 512 * 1048576);
-		return minFree;
+		return Math.min(minFree, 512 * 1024L * 1024L);
 	}
 
 	public static boolean isFreeMemoryAvailable() {
@@ -151,7 +150,7 @@ public class Utils {
 	}
 
 	private static String format(long mem) {
-		return Long.toString((long) (mem / 1024. / 1024.)) + "MB";
+		return (long) (mem / (double) (1024L * 1024L)) + "MB";
 	}
 
 	/**

jadx-gui/src/test/groovy/jadx/gui/tests/TestStringRef.groovy

 package jadx.gui.tests
+
 import jadx.gui.utils.search.StringRef
 import spock.lang.Specification
 

jadx-gui/src/test/java/jadx/gui/utils/CertificateManagerTest.java

 package jadx.gui.utils;
 
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.Test;
-
-import java.io.*;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
 import java.security.cert.Certificate;
 import java.util.Collection;
 
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
 
 public class CertificateManagerTest {
+	private static final String CERTIFICATE_TEST_DIR = "certificate-test/";
 	private static final String DSA = "CERT.DSA";
 	private static final String RSA = "CERT.RSA";
 	private static final String EMPTY = "EMPTY.txt";
+
 	private String emptyPath;
-    CertificateManager certificateManagerRSA;
-    CertificateManager certificateManagerDSA;
+	private CertificateManager certificateManagerRSA;
+	private CertificateManager certificateManagerDSA;
 
-    private CertificateManager getCertificateManger(String resName)
-    {
-        String sertPath = getClass().getClassLoader().getResource(resName).getPath();
-        try (InputStream in = new FileInputStream(sertPath)) {
+	private CertificateManager getCertificateManger(String resName) {
+		String certPath = getResourcePath(resName);
+		try (InputStream in = new FileInputStream(certPath)) {
 			Collection<? extends Certificate> certificates = CertificateManager.readCertificates(in);
-            Certificate cert =  (Certificate)certificates.toArray()[0];
+			Certificate cert = certificates.iterator().next();
 			return new CertificateManager(cert);
-        } catch (FileNotFoundException e) {
-            e.printStackTrace();
-        } catch (IOException e) {
-            e.printStackTrace();
+		} catch (Exception e) {
+			throw new RuntimeException("Failed to create CertificateManager");
 		}
-        return null;
 	}
 
 	@Before
 	public void setUp() {
-        emptyPath = getClass().getClassLoader().getResource(EMPTY).getPath();
+		emptyPath = getResourcePath(EMPTY);
 		certificateManagerRSA = getCertificateManger(RSA);
 		certificateManagerDSA = getCertificateManger(DSA);
 	}
 
-
 	@Test
-    public void decodeNotCertificateFile() {
+	public void decodeNotCertificateFile() throws IOException {
 		try (InputStream in = new FileInputStream(emptyPath)) {
 			String result = CertificateManager.decode(in);
-            Assert.assertEquals(result, "");
-        } catch (FileNotFoundException e) {
-            e.printStackTrace();
-        } catch (IOException e) {
-            e.printStackTrace();
+			Assert.assertEquals("", result);
 		}
 	}
 
@@ -58,7 +53,6 @@ public class CertificateManagerTest  {
 		Assert.assertTrue(string.contains("X.509"));
 		Assert.assertTrue(string.contains("0x4bd68052"));
 		Assert.assertTrue(string.contains("CN=test cert, OU=test unit, O=OOO TestOrg, L=St.Peterburg, ST=Russia, C=123456"));
-
 	}
 
 	@Test
@@ -67,46 +61,62 @@ public class CertificateManagerTest  {
 		Assert.assertTrue(string.contains("X.509"));
 		Assert.assertTrue(string.contains("0x16420ba2"));
 		Assert.assertTrue(string.contains("O=\"UJMRFVV CN=EDCVBGT C=TG\""));
-
 	}
+
 	@Test
 	public void decodeRSAKeySignature() {
 		String string = certificateManagerRSA.generateSignature();
 		Assert.assertTrue(string.contains("SHA256withRSA"));
 		Assert.assertTrue(string.contains("1.2.840.113549.1.1.11"));
 	}
+
 	@Test
 	public void decodeDSAKeySignature() {
 		String string = certificateManagerDSA.generateSignature();
 		Assert.assertTrue(string.contains("SHA1withDSA"));
 		Assert.assertTrue(string.contains("1.2.840.10040.4.3"));
 	}
+
 	@Test
 	public void decodeRSAFingerprint() {
 		String string = certificateManagerRSA.generateFingerprint();
 		Assert.assertTrue(string.contains("61 18 0A 71 3F C9 55 16 4E 04 E3 C5 45 08 D9 11"));
 		Assert.assertTrue(string.contains("A0 6E A6 06 DB 2C 6F 3A 16 56 7F 75 97 7B AE 85 C2 13 09 37"));
-        Assert.assertTrue(string.contains("12 53 E8 BB C8 AA 27 A8 49 9B F8 0D 6E 68 CE 32 35 50 DE 55 A7 E7 8C 29 51 00 96 D7 56 F4 54 44"));
+		Assert.assertTrue(string.contains("12 53 E8 BB C8 AA 27 A8 49 9B F8 0D 6E 68 CE 32 35 50 DE 55 A7 E7 8C 29 51 00 96 D7 56 F4 54 " +
+				"44"));
 	}
+
 	@Test
 	public void decodeDSAFingerprint() {
 		String string = certificateManagerDSA.generateFingerprint();
 		Assert.assertTrue(string.contains("D9 06 A6 2D 1F 79 8C 9D A6 EF 40 C7 2E C2 EA 0B"));
 		Assert.assertTrue(string.contains("18 E9 9C D4 A1 40 8F 63 FA EC 2E 62 A0 F2 AE B7 3F C3 C2 04"));
-        Assert.assertTrue(string.contains("74 F9 48 64 EE AC 92 26 53 2C 7A 0E 55 BE 5E D8 2F A7 D9 A9 99 F5 D5 21 2C 51 21 C4 31 AD 73 40"));
+		Assert.assertTrue(string.contains("74 F9 48 64 EE AC 92 26 53 2C 7A 0E 55 BE 5E D8 2F A7 D9 A9 99 F5 D5 21 2C 51 21 C4 31 AD 73 " +
+				"40"));
 	}
+
 	@Test
 	public void decodeRSAPubKey() {
 		String string = certificateManagerRSA.generatePublicKey();
 		Assert.assertTrue(string.contains("RSA"));
 		Assert.assertTrue(string.contains("65537"));
-        Assert.assertTrue(string.contains("16819531290318044625546437357099080306019392752925688951114880688329201213180109168890384305768067101521914473763638669503560977521269328582980060332888147680193318231260043189411794465899645633586173494259691101582064441956032924396850221679489313043628562082670183392670094163371858684118480409374749790551473773845213427476236147328434427272177623018935282929152308753854314219987617604037468769472089902090243358285991739642170211970862773121939911777280101937073243006335384636193260583579409760790138329893534549366882523130765297472656435892831796545149793228897111760122091442123535919361963075454640516520743"));
+		Assert.assertTrue(string.contains(
+				"16819531290318044625546437357099080306019392752925688951114880688329201213180109168890384305768067101521914473763638669503560977521269328582980060332888147680193318231260043189411794465899645633586173494259691101582064441956032924396850221679489313043628562082670183392670094163371858684118480409374749790551473773845213427476236147328434427272177623018935282929152308753854314219987617604037468769472089902090243358285991739642170211970862773121939911777280101937073243006335384636193260583579409760790138329893534549366882523130765297472656435892831796545149793228897111760122091442123535919361963075454640516520743"));
 	}
+
 	@Test
 	public void decodeDSAPubKey() {
 		String string = certificateManagerDSA.generatePublicKey();
 		Assert.assertTrue(string.contains("DSA"));
-        Assert.assertTrue(string.contains("19323367605058154682563301282345453222279312104889899001698209626254725581511375469963812461090495963838615773832867364330457010553974237985991904800958394169421485070378434746792379708805563793253282995274293621162504943287538455944652344378242226897507369146942411692220922477368782490423187845815262510366"));
+		Assert.assertTrue(string.contains(
+				"19323367605058154682563301282345453222279312104889899001698209626254725581511375469963812461090495963838615773832867364330457010553974237985991904800958394169421485070378434746792379708805563793253282995274293621162504943287538455944652344378242226897507369146942411692220922477368782490423187845815262510366"));
 	}
 
+	private String getResourcePath(String resName) {
+		URL resource = getClass().getClassLoader().getResource(CERTIFICATE_TEST_DIR + resName);
+		if (resource == null) {
+			throw new RuntimeException("Resource not found: " + resName);
+		}
+		return resource.getPath();
+	}
 }