refactor: migrate nullability annotations from SpotBugs to JSpecify

Replaces legacy JSR-305/SpotBugs annotations with the modern JSpecify
standard across the framework. This resolves longstanding JPMS split-package
warnings (javax.annotation), lightens the dependency tree, and modernizes
null-safety contracts.

Core & Global Changes:
- Removed `spotbugs-annotations` and `jsr305` dependencies entirely.
- Added `org.jspecify:jspecify` as the unified nullability standard.
- Swapped `@ReturnValuesAreNonnullByDefault` for `@NullMarked` in packages.
- Cleaned up redundant `@NonNull` annotations. JSpecify's `@NullMarked`
  applies a non-null default to the entire scope (returns, parameters,
  and fields), making explicit non-null declarations unnecessary.

jooby-apt (Annotation Processing):
- Added support for Type-Use annotations.
- Processors now correctly check both the element declaration AND the
  underlying return/parameter types (`asType().getAnnotationMirrors()`)
  to resolve nullability, fixing the visibility gap between legacy
  declaration annotations and modern type-use annotations.

jooby-openapi (ASM Bytecode Parsing):
- Overhauled parameter annotation extraction to gather type annotations
  (`visibleTypeAnnotations` & `invisibleTypeAnnotations`) alongside
  standard parameter arrays.
- Hardened nullability detection: replaced hardcoded JetBrains/SpotBugs
  descriptors with flexible substring matching ("Nullable", "NonNull",
  "NotNull"). The OpenAPI generator is now fully library-agnostic and
  will correctly parse JSpecify, JetBrains, Lombok, or SpotBugs annotations.

- fix  #3906

Author: jknack

docs/src/main/java/io/jooby/adoc/DocPostprocessor.java

@@ -8,7 +8,6 @@
 import java.util.Set;
 import java.util.UUID;
 
-import edu.umd.cs.findbugs.annotations.NonNull;
 import org.asciidoctor.extension.Postprocessor;
 import org.jcodings.util.Hash;
 import org.jsoup.Jsoup;
@@ -145,7 +144,6 @@ private static void headerIds(Document doc, int level) {
         });
   }
 
-  @NonNull
   private static String cleanId(String id) {
     return id.replaceAll("-\\d+$", "");
   }

jooby/pom.xml

@@ -14,8 +14,8 @@
   <dependencies>
 
     <dependency>
-      <groupId>com.github.spotbugs</groupId>
-      <artifactId>spotbugs-annotations</artifactId>
+      <groupId>org.jspecify</groupId>
+      <artifactId>jspecify</artifactId>
     </dependency>
 
     <!-- Logging System -->

jooby/src/main/java/io/jooby/AttachedFile.java

@@ -9,8 +9,6 @@
 import java.io.InputStream;
 import java.nio.file.Path;
 
-import edu.umd.cs.findbugs.annotations.NonNull;
-
 /**
  * Represents a file attachment response.
  *
@@ -26,7 +24,7 @@ public class AttachedFile extends FileDownload {
    * @param fileName Filename.
    * @param fileSize File size or <code>-1</code> if unknown.
    */
-  public AttachedFile(@NonNull InputStream content, @NonNull String fileName, long fileSize) {
+  public AttachedFile(InputStream content, String fileName, long fileSize) {
     super(Mode.ATTACHMENT, content, fileName, fileSize);
   }
 
@@ -36,7 +34,7 @@ public AttachedFile(@NonNull InputStream content, @NonNull String fileName, long
    * @param content File content.
    * @param fileName Filename.
    */
-  public AttachedFile(@NonNull InputStream content, @NonNull String fileName) {
+  public AttachedFile(InputStream content, String fileName) {
     super(Mode.ATTACHMENT, content, fileName);
   }
 
@@ -47,7 +45,7 @@ public AttachedFile(@NonNull InputStream content, @NonNull String fileName) {
    * @param fileName Filename.
    * @throws IOException For IO exception while reading file.
    */
-  public AttachedFile(@NonNull Path file, @NonNull String fileName) throws IOException {
+  public AttachedFile(Path file, String fileName) throws IOException {
     super(Mode.ATTACHMENT, file, fileName);
   }
 
@@ -57,7 +55,7 @@ public AttachedFile(@NonNull Path file, @NonNull String fileName) throws IOExcep
    * @param file File content.
    * @throws IOException For IO exception while reading file.
    */
-  public AttachedFile(@NonNull Path file) throws IOException {
+  public AttachedFile(Path file) throws IOException {
     super(Mode.ATTACHMENT, file);
   }
 }

jooby/src/main/java/io/jooby/Body.java

@@ -14,8 +14,8 @@
 import java.util.List;
 import java.util.Set;
 
-import edu.umd.cs.findbugs.annotations.NonNull;
-import edu.umd.cs.findbugs.annotations.Nullable;
+import org.jspecify.annotations.Nullable;
+
 import io.jooby.exception.MissingValueException;
 import io.jooby.internal.ByteArrayBody;
 import io.jooby.internal.FileBody;
@@ -39,7 +39,7 @@ public interface Body extends Value {
    * @param charset Charset.
    * @return Body as string.
    */
-  default String value(@NonNull Charset charset) {
+  default String value(Charset charset) {
     byte[] bytes = bytes();
     if (bytes.length == 0) {
       throw new MissingValueException("body");
@@ -99,7 +99,7 @@ default Iterator<Value> iterator() {
   InputStream stream();
 
   @Override
-  default <T> List<T> toList(@NonNull Class<T> type) {
+  default <T> List<T> toList(Class<T> type) {
     return to(Reified.list(type).getType());
   }
 
@@ -112,11 +112,11 @@ default <T> List<T> toList(@NonNull Class<T> type) {
   }
 
   @Override
-  default <T> T to(@NonNull Class<T> type) {
+  default <T> T to(Class<T> type) {
     return to((Type) type);
   }
 
-  default @Nullable @Override <T> T toNullable(@NonNull Class<T> type) {
+  default @Nullable @Override <T> T toNullable(Class<T> type) {
     return toNullable((Type) type);
   }
 
@@ -127,7 +127,7 @@ default <T> T to(@NonNull Class<T> type) {
    * @param <T> Generic type.
    * @return Converted value.
    */
-  <T> T to(@NonNull Type type);
+  <T> T to(Type type);
 
   /**
    * Convert this body into the given type.
@@ -136,7 +136,7 @@ default <T> T to(@NonNull Class<T> type) {
    * @param <T> Generic type.
    * @return Converted value or <code>null</code>.
    */
-  @Nullable <T> T toNullable(@NonNull Type type);
+  @Nullable <T> T toNullable(Type type);
 
   /* **********************************************************************************************
    * Factory methods:
@@ -149,7 +149,7 @@ default <T> T to(@NonNull Class<T> type) {
    * @param ctx Current context.
    * @return Empty body.
    */
-  static Body empty(@NonNull Context ctx) {
+  static Body empty(Context ctx) {
     return ByteArrayBody.empty(ctx);
   }
 
@@ -161,7 +161,7 @@ static Body empty(@NonNull Context ctx) {
    * @param size Size in bytes or <code>-1</code>.
    * @return A new body.
    */
-  static Body of(@NonNull Context ctx, @NonNull InputStream stream, long size) {
+  static Body of(Context ctx, InputStream stream, long size) {
     return new InputStreamBody(ctx, stream, size);
   }
 
@@ -172,7 +172,7 @@ static Body of(@NonNull Context ctx, @NonNull InputStream stream, long size) {
    * @param bytes byte array.
    * @return A new body.
    */
-  static Body of(@NonNull Context ctx, @NonNull byte[] bytes) {
+  static Body of(Context ctx, byte[] bytes) {
     return new ByteArrayBody(ctx, bytes);
   }
 
@@ -183,7 +183,7 @@ static Body of(@NonNull Context ctx, @NonNull byte[] bytes) {
    * @param file File.
    * @return A new body.
    */
-  static Body of(@NonNull Context ctx, @NonNull Path file) {
+  static Body of(Context ctx, Path file) {
     return new FileBody(ctx, file);
   }
 }

jooby/src/main/java/io/jooby/ByteRange.java

@@ -8,8 +8,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 
-import edu.umd.cs.findbugs.annotations.NonNull;
-import edu.umd.cs.findbugs.annotations.Nullable;
+import org.jspecify.annotations.Nullable;
+
 import io.jooby.internal.NoByteRange;
 import io.jooby.internal.NotSatisfiableByteRange;
 import io.jooby.internal.SingleByteRange;
@@ -44,7 +44,7 @@ public interface ByteRange {
    * @param contentLength Content length.
    * @return Byte range instance.
    */
-  static @NonNull ByteRange parse(@Nullable String value, long contentLength) {
+  static ByteRange parse(@Nullable String value, long contentLength) {
     if (contentLength <= 0 || value == null) {
       // NOOP
       return new NoByteRange(contentLength);
@@ -129,7 +129,7 @@ public interface ByteRange {
    *
    * @return Value for <code>Content-Range</code> response header.
    */
-  @NonNull String getContentRange();
+  String getContentRange();
 
   /**
    * For partial requests this method returns {@link StatusCode#PARTIAL_CONTENT}.
@@ -141,7 +141,7 @@ public interface ByteRange {
    *
    * @return Status code.
    */
-  @NonNull StatusCode getStatusCode();
+  StatusCode getStatusCode();
 
   /**
    * For partial request this method set the following byte range response headers:
@@ -157,7 +157,7 @@ public interface ByteRange {
    * @param ctx Web context.
    * @return This byte range request.
    */
-  @NonNull ByteRange apply(@NonNull Context ctx);
+  ByteRange apply(Context ctx);
 
   /**
    * For partial requests this method generates a new truncated input stream.
@@ -170,5 +170,5 @@ public interface ByteRange {
    * @return A truncated input stream for partial request or same input stream.
    * @throws IOException When truncation fails.
    */
-  @NonNull InputStream apply(@NonNull InputStream input) throws IOException;
+  InputStream apply(InputStream input) throws IOException;
 }

jooby/src/main/java/io/jooby/CompletionListeners.java

@@ -9,8 +9,6 @@
 import java.util.List;
 import java.util.stream.Stream;
 
-import edu.umd.cs.findbugs.annotations.NonNull;
-
 /**
  * Utility class that group one or more completion listeners and execute them in reverse order.
  *
@@ -28,7 +26,7 @@ public CompletionListeners() {}
    *
    * @param listener Listener.
    */
-  public void addListener(@NonNull Route.Complete listener) {
+  public void addListener(Route.Complete listener) {
     if (listeners == null) {
       listeners = new ArrayList<>();
     }
@@ -40,7 +38,7 @@ public void addListener(@NonNull Route.Complete listener) {
    *
    * @param ctx Listeners.
    */
-  public void run(@NonNull Context ctx) {
+  public void run(Context ctx) {
     if (listeners != null) {
       Throwable cause = null;
       for (int i = listeners.size() - 1; i >= 0; i--) {