Multi-release jar.

Author: Maxim Butov

.github/workflows/build.yml

@@ -20,6 +20,7 @@ jobs:
           java-version: |
             8
             9
+            15
             16
             17
           distribution: 'adopt'
@@ -31,6 +32,6 @@ jobs:
         with:
           gradle-version: wrapper
           arguments: |
-            -Porg.gradle.java.installations.fromEnv=JAVA_HOME_8_X64,JAVA_HOME_9_X64,JAVA_HOME_16_X64,JAVA_HOME_17_X64 
+            -Porg.gradle.java.installations.fromEnv=JAVA_HOME_8_X64,JAVA_HOME_9_X64,JAVA_HOME_15_X64,JAVA_HOME_16_X64,JAVA_HOME_17_X64 
             clean 
             build

checkstyle/checkstyle.xml

@@ -186,7 +186,7 @@
         </module>
 
         <module name="TypeName">
-            <property name="format" value="^[A-Z][a-zA-Z0-9]*$"/>
+            <property name="format" value="^[A-Z\$][a-zA-Z0-9\$]*$"/>
             <property name="applyToPublic" value="true"/>
             <property name="applyToProtected" value="true"/>
             <property name="applyToPackage" value="true"/>

jdk15/build.gradle.kts

@@ -0,0 +1,23 @@
+plugins {
+    id("java-conventions")
+    id("optional-dependencies")
+    id("checkstyle-conventions")
+    id("build-utils")
+}
+
+dependencies {
+
+    implementation(project(":jdk8"))
+    implementation(project(":jdk9"))
+
+    testImplementation(testFixtures(project(":jdk8")))
+    testImplementation("org.hamcrest:hamcrest:2.2")
+    testImplementation("org.junit.jupiter:junit-jupiter:5.10.0")
+
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(15))
+    }
+}

jdk9/src/main/java/io/github/sugarcubes/cloner/Jdk15ConfigurationImpl.java renamed to jdk15/src/main/java/io/github/sugarcubes/cloner/JdkConfigurationImpl$Jdk15.java

@@ -23,7 +23,7 @@
  *
  * @author Maxim Butov
  */
-class Jdk15ConfigurationImpl extends Jdk9ConfigurationImpl {
+class JdkConfigurationImpl$Jdk15 extends JdkConfigurationImpl$Jdk9 {
 
     @Override
     public void initialize() {

jdk15/src/main/java/io/github/sugarcubes/cloner/JdkConfigurationImpl.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2017-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.github.sugarcubes.cloner;
+
+/**
+ * Actual JDK configuration.
+ */
+final class JdkConfigurationImpl extends JdkConfigurationImpl$Jdk15 {
+
+}

jdk16/build.gradle.kts

@@ -9,6 +9,7 @@ dependencies {
 
     implementation(project(":jdk8"))
     implementation(project(":jdk9"))
+    implementation(project(":jdk15"))
 
     testImplementation(testFixtures(project(":jdk8")))
     testImplementation("org.hamcrest:hamcrest:2.2")

jdk16/src/main/java/io/github/sugarcubes/cloner/Jdk16ConfigurationImpl.java renamed to jdk16/src/main/java/io/github/sugarcubes/cloner/JdkConfigurationImpl$Jdk16.java

@@ -20,7 +20,7 @@
  *
  * @author Maxim Butov
  */
-class Jdk16ConfigurationImpl extends Jdk15ConfigurationImpl {
+class JdkConfigurationImpl$Jdk16 extends JdkConfigurationImpl$Jdk15 {
 
     @Override
     @SuppressWarnings({"unchecked", "rawtypes"})

jdk16/src/main/java/io/github/sugarcubes/cloner/JdkConfigurationImpl.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2017-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.github.sugarcubes.cloner;
+
+/**
+ * Actual JDK configuration.
+ */
+final class JdkConfigurationImpl extends JdkConfigurationImpl$Jdk16 {
+
+}

jdk8/src/main/java/io/github/sugarcubes/cloner/JdkConfiguration.java

@@ -27,7 +27,8 @@ interface JdkConfiguration {
     /**
      * Initializes configuration.
      */
-    void initialize();
+    default void initialize() {
+    }
 
     /**
      * Returns immutable types.

jdk8/src/main/java/io/github/sugarcubes/cloner/JdkConfigurationHolder.java

@@ -22,37 +22,10 @@
  */
 class JdkConfigurationHolder {
 
-    static final JdkConfiguration CONFIGURATION;
+    static final JdkConfiguration CONFIGURATION = new JdkConfigurationImpl();
 
     static {
-        JdkConfiguration configuration = null;
-
-        String packageName = JdkConfigurationHolder.class.getPackage().getName();
-        for (int version = JdkVersion.CURRENT.version; version >= JdkVersion.MINIMAL.version; version--) {
-            String configurationClassName = String.format("%s.Jdk%dConfigurationImpl", packageName, version);
-            Class<JdkConfiguration> configurationClass;
-            try {
-                configurationClass = (Class<JdkConfiguration>) Class.forName(configurationClassName);
-            }
-            catch (ClassNotFoundException e) {
-                continue;
-            }
-            try {
-                configuration = configurationClass.getDeclaredConstructor().newInstance();
-            }
-            catch (Exception e) {
-                throw new ClonerException("Cannot instantiate configuration.", e);
-            }
-            break;
-        }
-
-        if (configuration == null) {
-            throw Checks.mustNotHappen();
-        }
-
-        CONFIGURATION = configuration;
-
-        configuration.initialize();
+        CONFIGURATION.initialize();
     }
 
 }