Enable compiler linting and fix all errors

Closes gh-1653

Author: mhalbritter

initializr-generator/src/main/java/io/spring/initializr/generator/language/Annotation.java

@@ -244,7 +244,7 @@ public enum AttributeType {
 		CLASS() {
 			@Override
 			protected Collection<String> getImports(Object value) {
-				if (value instanceof Class type) {
+				if (value instanceof Class<?> type) {
 					return List.of(type.getName());
 				}
 				else if (value instanceof ClassName name) {
@@ -260,7 +260,7 @@ else if (value instanceof ClassName name) {
 		ENUM() {
 			@Override
 			protected Collection<String> getImports(Object value) {
-				if (value instanceof Enum enumeration) {
+				if (value instanceof Enum<?> enumeration) {
 					return List.of(enumeration.getClass().getName());
 				}
 				return super.getImports(value);
@@ -408,7 +408,7 @@ private CodeBlock generateValueCode(AttributeType attributeType, Object value) {
 				}
 				case STRING -> CodeBlock.of("$S", value);
 				case CLASS -> {
-					ClassName className = (value instanceof Class clazz) ? ClassName.of(clazz) : (ClassName) value;
+					ClassName className = (value instanceof Class<?> clazz) ? ClassName.of(clazz) : (ClassName) value;
 					yield this.formattingOptions.classReference(className);
 				}
 				case ENUM -> {

initializr-generator/src/main/java/io/spring/initializr/generator/language/CodeBlock.java

@@ -284,7 +284,7 @@ private String argToString(Object arg) {
 		}
 
 		private String argToType(Object arg) {
-			if (arg instanceof Class type) {
+			if (arg instanceof Class<?> type) {
 				this.imports.add(type.getName());
 				return type.getSimpleName();
 			}

initializr-generator/src/main/java/io/spring/initializr/generator/version/VersionProperty.java

@@ -16,6 +16,7 @@
 
 package io.spring.initializr.generator.version;
 
+import java.io.Serial;
 import java.io.Serializable;
 import java.util.Arrays;
 import java.util.List;
@@ -32,6 +33,9 @@
  */
 public final class VersionProperty implements Serializable, Comparable<VersionProperty> {
 
+	@Serial
+	private static final long serialVersionUID = 1L;
+
 	private static final List<Character> SUPPORTED_CHARS = Arrays.asList('.', '-');
 
 	private final String property;

initializr-parent/pom.xml

@@ -183,6 +183,10 @@
 						<parameters>true</parameters>
 						<failOnWarning>true</failOnWarning>
 						<showDeprecation>true</showDeprecation>
+						<compilerArgs>
+							<arg>-Xlint:all</arg>
+							<arg>-Xlint:-processing</arg>
+						</compilerArgs>
 					</configuration>
 				</plugin>
 				<plugin>

initializr-web/src/main/java/io/spring/initializr/web/autoconfigure/InitializrModule.java

@@ -17,6 +17,7 @@
 package io.spring.initializr.web.autoconfigure;
 
 import java.io.IOException;
+import java.io.Serial;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.SerializerProvider;
@@ -31,13 +32,19 @@
  */
 class InitializrModule extends SimpleModule {
 
+	@Serial
+	private static final long serialVersionUID = 1L;
+
 	InitializrModule() {
 		super("initializr");
 		addSerializer(new VersionPropertySerializer());
 	}
 
 	private static class VersionPropertySerializer extends StdSerializer<VersionProperty> {
 
+		@Serial
+		private static final long serialVersionUID = 1L;
+
 		VersionPropertySerializer() {
 			super(VersionProperty.class);
 		}