refact: improve null safety

jstuff-core/src/main/java/net/sf/jstuff/core/SystemUtils.java

@@ -46,8 +46,8 @@ public abstract class SystemUtils extends org.apache.commons.lang3.SystemUtils {
 
  private static final Collection<String> WINDOWS_EXE_FILE_EXTENSIONS = List.of(Strings.splitByWholeSeparator( //
  IS_OS_WINDOWS //
- ? getEnvironmentVariable("PATHEXT", "") //
- : ".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC", //
+  ? getEnvironmentVariable("PATHEXT", "") //
+  : ".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC", //
  ";" //
  ));
 
@@ -119,8 +119,8 @@ public static String getEnvironmentVariable(final String name, final String defa
  public static int getJavaMajorVersion() {
  final String version = asNonNull(System.getProperty("java.version"));
  return Integer.parseInt(version.startsWith("1.") //
- ? version.substring(2, 3) //
- : Strings.substringBefore(version, '.') //
+  ? version.substring(2, 3) //
+  : Strings.substringBefore(version, '.') //
  );
  }
 
@@ -170,7 +170,9 @@ public static boolean isRunningAsAdmin() {
  }
 
  final java.util.logging.Logger prefsLogger = LogManager.getLogManager().getLogger("java.util.prefs.WindowsPreferences");
- prefsLogger.setLevel(Level.SEVERE);
+ if (prefsLogger != null) {
+ prefsLogger.setLevel(Level.SEVERE);
+ }
  try {
  // https://stackoverflow.com/a/23538961/5116073
  final Preferences prefs = Preferences.systemRoot();
@@ -182,7 +184,9 @@ public static boolean isRunningAsAdmin() {
  isRunningAsAdmin = true;
  return true;
  } finally {
- prefsLogger.setLevel(Level.INFO);
+ if (prefsLogger != null) {
+ prefsLogger.setLevel(Level.INFO);
+ }
  }
  } catch (final Exception ex) {
  LOG.debug(ex);

jstuff-core/src/main/java/net/sf/jstuff/core/benchmark/package-info.java

@@ -4,7 +4,9 @@
  *
  * @author Sebastian Thomschke
  */
-@NonNullByDefault
+@NonNullByDefault({ARRAY_CONTENTS, FIELD, PARAMETER, RETURN_TYPE, TYPE_ARGUMENT, TYPE_BOUND, TYPE_PARAMETER})
 package net.sf.jstuff.core.benchmark;
 
+import static org.eclipse.jdt.annotation.DefaultLocation.*;
+
 import org.eclipse.jdt.annotation.NonNullByDefault;

jstuff-core/src/main/java/net/sf/jstuff/core/builder/BuilderFactory.java

@@ -15,7 +15,6 @@
 import java.util.Set;
 
 import org.apache.commons.lang3.ArrayUtils;
-import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
 
 import net.sf.jstuff.core.Strings;
@@ -32,7 +31,7 @@
 /**
  * @author <a href="https://sebthom.de/">Sebastian Thomschke</a>
  */
-public class BuilderFactory<TARGET_CLASS, @NonNull BLDR_IFACE extends Builder<? extends TARGET_CLASS>> {
+public class BuilderFactory<TARGET_CLASS, BLDR_IFACE extends Builder<? extends TARGET_CLASS>> {
 
  private static final class BuilderImpl implements InvocationHandler {
 
@@ -47,7 +46,7 @@ private static final class BuilderImpl implements InvocationHandler {
  /**
  * ordered list of the values of all wither/setter invocations on the builder instance
  */
- private final List<Tuple2<String, Object[]>> properties = new ArrayList<>();
+ private final List<Tuple2<String, @Nullable Object[]>> properties = new ArrayList<>();
 
  BuilderImpl(final Class<?> builderInterface, final Class<?> targetClass, final Object... constructorArgs) {
  this.builderInterface = builderInterface;
@@ -124,14 +123,13 @@ protected Object buildTarget() throws Throwable { // CHECKSTYLE:IGNORE .*
  final Object target = Types.newInstance(targetClass, constructorArgs);
 
  // setting properties
- for (final Tuple2<String, Object[]> property : properties) {
- @NonNull
+ for (final Tuple2<String, @Nullable Object[]> property : properties) {
  String propName = property.get1();
  // remove "with" prefix from withSomeProperty(...) named properties
  if (propName.length() > 4 && propName.startsWith("with")) {
  propName = Strings.lowerCaseFirstChar(propName.substring(4));
  }
- final Object[] propArgs = property.get2();
+ final @Nullable Object[] propArgs = property.get2();
  final String setterName = "set" + Strings.upperCaseFirstChar(propName);
  final Method setterMethod = Methods.findAnyCompatible(targetClass, setterName, propArgs);
  // if no setter found then directly try to set the field
@@ -151,7 +149,7 @@ protected Object buildTarget() throws Throwable { // CHECKSTYLE:IGNORE .*
  final Builder.Property propConfig = prop.getValue();
 
  boolean wasPropertySet = false;
- for (final Tuple2<String, Object[]> property : properties) {
+ for (final Tuple2<String, @Nullable Object[]> property : properties) {
  if (propName.equals(property.get1())) {
  final boolean isNullable = propConfig == null ? propertyDefaults.nullable() : propConfig.nullable();
  if (!isNullable && property.get2()[0] == null)
@@ -189,7 +187,7 @@ protected Object buildTarget() throws Throwable { // CHECKSTYLE:IGNORE .*
  * handles invocation of withXYZ on builder interface
  */
  @Override
- public @Nullable Object invoke(final Object proxy, final Method method, final Object @Nullable [] args) throws Throwable {
+ public @Nullable Object invoke(final Object proxy, final Method method, final @Nullable Object @Nullable [] args) throws Throwable {
  final boolean isBuildMethod = "build".equals(method.getName()) //
  && method.getParameterTypes().length == 0 //
  && method.getReturnType().isAssignableFrom(targetClass);
@@ -202,7 +200,7 @@ protected Object buildTarget() throws Throwable { // CHECKSTYLE:IGNORE .*
 
  // collect values from setter invocations
  if (method.getReturnType().isAssignableFrom(builderInterface)) {
- properties.add(Tuple2.create(method.getName(), args == null ? ArrayUtils.EMPTY_OBJECT_ARRAY : args));
+ properties.add(new Tuple2<>(method.getName(), args == null ? new @Nullable Object[0] : args));
  return proxy;
  }
  throw new UnsupportedOperationException(method.toString());

jstuff-core/src/main/java/net/sf/jstuff/core/builder/package-info.java

@@ -4,7 +4,9 @@
  *
  * @author Sebastian Thomschke
  */
-@NonNullByDefault
+@NonNullByDefault({ARRAY_CONTENTS, FIELD, PARAMETER, RETURN_TYPE, TYPE_ARGUMENT, TYPE_BOUND, TYPE_PARAMETER})
 package net.sf.jstuff.core.builder;
 
+import static org.eclipse.jdt.annotation.DefaultLocation.*;
+
 import org.eclipse.jdt.annotation.NonNullByDefault;

jstuff-core/src/main/java/net/sf/jstuff/core/classloader/package-info.java

@@ -4,7 +4,9 @@
  *
  * @author Sebastian Thomschke
  */
-@NonNullByDefault
+@NonNullByDefault({ARRAY_CONTENTS, FIELD, PARAMETER, RETURN_TYPE, TYPE_ARGUMENT, TYPE_BOUND, TYPE_PARAMETER})
 package net.sf.jstuff.core.classloader;
 
+import static org.eclipse.jdt.annotation.DefaultLocation.*;
+
 import org.eclipse.jdt.annotation.NonNullByDefault;

jstuff-core/src/main/java/net/sf/jstuff/core/collection/Maps.java

@@ -4,7 +4,7 @@
  */
 package net.sf.jstuff.core.collection;
 
-import static net.sf.jstuff.core.validation.NullAnalysisHelper.asNonNullUnsafe;
+import static net.sf.jstuff.core.validation.NullAnalysisHelper.*;
 
 import java.io.Serializable;
 import java.util.ArrayList;
@@ -21,6 +21,8 @@
 import java.util.WeakHashMap;
 
 import org.apache.commons.lang3.ObjectUtils;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 
 import net.sf.jstuff.core.Strings;
@@ -49,7 +51,7 @@ public static class EntryValueDiff<K, V> implements Serializable {
  public final @Nullable V rightValue;
 
  public EntryValueDiff(final Map<K, V> leftMap, final Map<K, V> rightMap, final K key, final @Nullable V leftValue,
- final @Nullable V rightValue) {
+  final @Nullable V rightValue) {
  this.leftMap = leftMap;
  this.rightMap = rightMap;
  this.key = key;
@@ -84,7 +86,7 @@ public boolean isDifferent() {
  @Override
  public String toString() {
  return MapDiff.class.getSimpleName() + " [entryValueDiffs=" + entryValueDiffs + ", leftOnlyEntries=" + leftOnlyEntries
- + ", rightOnlyEntries=" + rightOnlyEntries + "]";
+  + ", rightOnlyEntries=" + rightOnlyEntries + "]";
  }
  }
 
@@ -186,7 +188,7 @@ public static <K, V> HashMap<K, V> newHashMap(final int initialSize) {
  }
 
  public static <K, V, KK extends K, VV extends V> HashMap<K, V> newHashMap(final KK firstKey, final VV firstValue,
- final Object... moreInitialKeysAndValues) {
+  final Object... moreInitialKeysAndValues) {
  return putAll(new HashMap<>(1 + moreInitialKeysAndValues.length / 2), firstKey, firstValue, moreInitialKeysAndValues);
  }
 
@@ -210,7 +212,7 @@ public static <K, V> LinkedHashMap<K, V> newLinkedHashMap(final int initialSize)
  }
 
  public static <K, V, KK extends K, VV extends V> LinkedHashMap<K, V> newLinkedHashMap(final KK firstKey, final VV firstValue,
- final Object... moreInitialKeysAndValues) {
+  final Object... moreInitialKeysAndValues) {
  return putAll(new LinkedHashMap<>(1 + moreInitialKeysAndValues.length / 2), firstKey, firstValue, moreInitialKeysAndValues);
  }
 
@@ -238,20 +240,20 @@ public static <K, V> TreeMap<K, V> newTreeMap(final Comparator<? super K> keyCom
  }
 
  public static <K, V, KK extends K, VV extends V> TreeMap<K, V> newTreeMap(final Comparator<? super K> keyComparator, final KK firstKey,
- final VV firstValue, final Object... moreInitialKeysAndValues) {
+  final VV firstValue, final Object... moreInitialKeysAndValues) {
  return putAll(new TreeMap<>(keyComparator), firstKey, firstValue, moreInitialKeysAndValues);
  }
 
  public static <K, V, KK extends K, VV extends V> TreeMap<K, V> newTreeMap(final Comparator<? super K> keyComparator,
- final Object @Nullable [] initialKeysAndValues) {
+  final Object @Nullable [] initialKeysAndValues) {
  if (initialKeysAndValues == null)
  return new TreeMap<>(keyComparator);
 
  return putAll(new TreeMap<>(keyComparator), initialKeysAndValues);
  }
 
  public static <K, V, KK extends K, VV extends V> TreeMap<K, V> newTreeMap(final KK firstKey, final VV firstValue,
- final Object... moreInitialKeysAndValues) {
+  final Object... moreInitialKeysAndValues) {
  return putAll(new TreeMap<>(), firstKey, firstValue, moreInitialKeysAndValues);
  }
 
@@ -271,7 +273,7 @@ public static <K, V, M extends Map<K, V>> M putAll(final M map, final K[] keys,
 
  @SuppressWarnings("unchecked")
  public static <K, V, KK extends K, VV extends V, M extends Map<K, V>> M putAll(final M map, final KK firstKey, final VV firstValue,
- final Object... moreKeysAndValues) {
+  final Object... moreKeysAndValues) {
  Args.notNull("map", map);
 
  map.put(firstKey, firstValue);
@@ -338,7 +340,7 @@ public static <K, V, M extends Map<K, V>> M putAllIfAbsent(final M map, final K[
 
  @SuppressWarnings("unchecked")
  public static <K, V, KK extends K, VV extends V, M extends Map<K, V>> M putAllIfAbsent(final M map, final KK firstKey,
- final VV firstValue, final Object... moreKeysAndValues) {
+  final VV firstValue, final Object... moreKeysAndValues) {
  Args.notNull("map", map);
 
  map.put(firstKey, firstValue);
@@ -378,7 +380,8 @@ public static <K, V, M extends Map<K, V>> M putAllIfAbsent(final M map, final Ob
  return map;
  }
 
- public static <K, V extends Comparable<V>> Map<K, V> sortByValue(final Map<K, V> map) {
+ @NonNullByDefault({})
+ public static <K, V extends Comparable<V>> @NonNull Map<K, V> sortByValue(final @NonNull Map<K, V> map) {
  return sortByValue(map, SortDirection.ASC);
  }
 
@@ -400,7 +403,9 @@ public static <K, V> Map<K, V> sortByValue(final Map<K, V> map, final Comparator
  return sortedMap;
  }
 
- public static <K, V extends Comparable<V>> Map<K, V> sortByValue(final Map<K, V> map, final SortDirection direction) {
+ @NonNullByDefault({})
+ public static <K, V extends Comparable<V>> @NonNull Map<K, V> sortByValue(final @NonNull Map<K, V> map,
+ final @NonNull SortDirection direction) {
  Args.notNull("map", map);
 
  if (map.isEmpty())
@@ -460,14 +465,13 @@ public static <T> Map<T, T> toMap(final T... keysAndValues) {
 
  final var result = new HashMap<T, T>();
  boolean isKey = true;
- @Nullable
- T key = null;
+ T key = lazyNonNull();
  for (final T item : keysAndValues)
  if (isKey) {
  key = item;
  isKey = false;
  } else {
- result.put(key, item);
+ result.put(asNonNullUnsafe(key), item);
  isKey = true;
  }
  return result;

jstuff-core/src/main/java/net/sf/jstuff/core/event/DebouncingEventDispatcher.java

@@ -98,10 +98,10 @@ public DebouncingEventDispatcher(final Duration delay) {
  }
 
  private DebouncingEventDispatcher( //
- final Duration delay, //
- final @Nullable EventDispatcher<EVENT> delegate, //
- final @Nullable Function<EVENT, Object> eventKeyProvider, //
- final @Nullable ScheduledExecutorService scheduler //
+  final Duration delay, //
+  final @Nullable EventDispatcher<EVENT> delegate, //
+  final @Nullable Function<EVENT, Object> eventKeyProvider, //
+  final @Nullable ScheduledExecutorService scheduler //
  ) {
  super(delegate, eventKeyProvider, scheduler);
 
@@ -115,8 +115,8 @@ private DebouncingEventDispatcher( //
  @Override
  public CompletableFuture<Integer> fire(final EVENT event) {
  final long deadline = System.currentTimeMillis() + delayMS;
- return rateLimitedEvents.compute(eventKeyProvider.apply(event), (k, debouncedEvent) -> {
- if (asNullable(debouncedEvent) == null) {
+ return asNonNull(rateLimitedEvents.compute(eventKeyProvider.apply(event), (k, debouncedEvent) -> {
+ if (debouncedEvent == null) {
  debouncedEvent = new DebouncedEvent(event, deadline);
  final var remainingMS = Math.max(0, debouncedEvent.deadline - System.currentTimeMillis());
  debouncedEvent.scheduledFuture = scheduler.schedule(debouncedEvent::fireEvent, remainingMS, TimeUnit.MILLISECONDS);
@@ -126,11 +126,11 @@ public CompletableFuture<Integer> fire(final EVENT event) {
 
  final var remainingMS = debouncedEvent.deadline - System.currentTimeMillis();
  debouncedEvent.scheduledFuture = remainingMS < 1 //
- ? scheduler.submit(debouncedEvent::fireEvent) //
- : scheduler.schedule(debouncedEvent::fireEvent, //
- remainingMS, TimeUnit.MILLISECONDS);
+  ? scheduler.submit(debouncedEvent::fireEvent) //
+  : scheduler.schedule(debouncedEvent::fireEvent, //
+  remainingMS, TimeUnit.MILLISECONDS);
  }
  return debouncedEvent;
- }).resultFuture;
+ })).resultFuture;
  }
 }

jstuff-core/src/main/java/net/sf/jstuff/core/jmx/JMXUtils.java

@@ -21,8 +21,7 @@
 public abstract class JMXUtils {
  private static final Logger LOG = Logger.create();
 
- @Nullable
- private static MBeanServer mbeanServer;
+ private static @Nullable MBeanServer mbeanServer;
 
  public static synchronized MBeanServer getMBeanServer() {
  var mbeanServer = JMXUtils.mbeanServer;
@@ -77,7 +76,7 @@ public static boolean isDebugModeEnabled() {
  final List<String> args = ManagementFactory.getRuntimeMXBean().getInputArguments();
  for (final String arg : args) {
  if (arg.startsWith("-agentlib:jdwp") && args.contains("-Xdebug") //
- || arg.startsWith("-Xrunjdwp"))
+  || arg.startsWith("-Xrunjdwp"))
  return true;
  }
  return false;

jstuff-core/src/main/java/net/sf/jstuff/core/net/NetUtils.java

@@ -107,8 +107,12 @@ public static long getLastModified(final URL resourceURL) throws IOException {
  * Get the resource URL via this.getClass().getResource("....").
  */
  public static long getLastModified(final URLConnection resourceConnection) throws IOException {
- if (resourceConnection instanceof JarURLConnection)
- return ((JarURLConnection) resourceConnection).getJarEntry().getTime();
+ if (resourceConnection instanceof JarURLConnection) {
+ final var jarURL = (JarURLConnection) resourceConnection;
+ final var entry = jarURL.getJarEntry();
+ if (entry != null)
+ return entry.getTime();
+ }
 
  /*
  * Because of a bug in Suns VM regarding FileURLConnection, which for some reason causes 0 to be

jstuff-core/src/main/java/net/sf/jstuff/core/net/TcpTunnelService.java

@@ -74,11 +74,12 @@ public void run() {
  protected TcpTunnel(final Socket clientSocket) throws SocketException {
  this.clientSocket = clientSocket;
  tunnelName = clientSocket.getInetAddress().getHostAddress() + ":" + clientSocket.getPort() + " > " //
- + clientSocket.getLocalAddress().getHostName() + ":" + clientSocket.getLocalPort() + " > " //
- + (Strings.isBlank(proxyAddress) ? "" : proxyAddress + ":" + proxyPort + " > ") //
- + targetAddress + ":" + targetPort;
+  + clientSocket.getLocalAddress().getHostName() + ":" + clientSocket.getLocalPort() + " > " //
+  + (Strings.isBlank(proxyAddress) ? "" : proxyAddress + ":" + proxyPort + " > ") //
+  + targetAddress + ":" + targetPort;
 
- if (Strings.isBlank(proxyAddress)) {
+ final var proxyType = TcpTunnelService.this.proxyType;
+ if (proxyType == null || Strings.isBlank(proxyAddress)) {
  targetSocket = new Socket();
  } else {
  targetSocket = new Socket(new Proxy(proxyType, new InetSocketAddress(proxyAddress, proxyPort)));
@@ -121,7 +122,7 @@ public void run() {
  }
 
  public interface TcpProxyServerBuilder<THIS extends TcpProxyServerBuilder<THIS, T>, T extends TcpTunnelService> extends
- net.sf.jstuff.core.builder.Builder<TcpTunnelService> {
+  net.sf.jstuff.core.builder.Builder<TcpTunnelService> {
 
  /**
  * Default is -1, i.e. unlimited