Update Gradle, use Java 21, fix Javadoc issues

Author: octylFractal

.github/workflows/gradle.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Set up JDK
         uses: actions/setup-java@v4
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'temurin'
 
       - name: Setup Gradle

build-logic/build.gradle.kts

@@ -16,7 +16,7 @@ dependencies {
 }
 
 configure<JavaPluginExtension> {
-    toolchain.languageVersion.set(JavaLanguageVersion.of(17))
+    toolchain.languageVersion.set(JavaLanguageVersion.of(21))
 }
 
 gradlePlugin {

build-logic/src/main/kotlin/org/enginehub/gradle/JvmPlugin.kt

@@ -21,7 +21,7 @@ class JvmPlugin : Plugin<Project> {
                 mavenCentral()
             }
             configure<JavaPluginExtension> {
-                toolchain.languageVersion.set(JavaLanguageVersion.of(17))
+                toolchain.languageVersion.set(JavaLanguageVersion.of(21))
                 withJavadocJar()
                 withSourcesJar()
             }

common/src/main/java/org/enginehub/linbus/common/internal/AbstractIterator.java

@@ -35,6 +35,12 @@ public abstract class AbstractIterator<T extends @Nullable Object> implements It
     private boolean end;
     private T next;
 
+    /**
+     * Create a new iterator.
+     */
+    public AbstractIterator() {
+    }
+
     /**
      * Compute the next item.
      *

format-snbt/src/main/java/org/enginehub/linbus/format/snbt/impl/Elusion.java

@@ -21,7 +21,7 @@
 /**
  * Escape helpers.
  */
-public class Elusion {
+public final class Elusion {
     /**
      * Is {@code c} a character than can be emitted without quotes?
      *
@@ -78,4 +78,7 @@ public static CharSequence escapeIfNeeded(String s) {
         builder.append(quoteChar);
         return builder;
     }
+
+    private Elusion() {
+    }
 }

format-snbt/src/main/java/org/enginehub/linbus/format/snbt/impl/LinSnbtWriter.java

@@ -47,6 +47,12 @@ record WritingArray() implements WriteState {
 
     private final ArrayDeque<WriteState> stateStack = new ArrayDeque<>();
 
+    /**
+     * Construct a new writer.
+     */
+    public LinSnbtWriter() {
+    }
+
     /**
      * Write the tokens to the output.
      *

format-snbt/src/main/java/org/enginehub/linbus/format/snbt/impl/reader/SnbtToken.java

@@ -131,6 +131,9 @@ public String toString() {
 
     /**
      * String literal for arbitrary text.
+     *
+     * @param quoted if the text was quoted
+     * @param content the content of the text
      */
     record Text(boolean quoted, String content) implements SnbtToken {
     }

gradle/gradle-daemon-jvm.properties

@@ -0,0 +1,2 @@
+#This file is generated by updateDaemonJvm
+toolchainVersion=21

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME