GH-100 - Polishing.

Added missing license header. Simplify SimpleAssociation.equals(…).

kmolecules-ddd/src/main/kotlin/org/jmolecules/ddd/types/SimpleAssociation.kt

@@ -38,9 +38,7 @@ class SimpleAssociation<T : AggregateRoot<T, ID>, ID : Identifier>(private val i
 
         other as SimpleAssociation<*, *>
 
-        if (id != other.id) return false
-
-        return true
+        return id == other.id
     }
 
     override fun hashCode(): Int = id.hashCode()

kmolecules-ddd/src/main/kotlin/org/jmolecules/ddd/types/ValueObject.kt

@@ -1,8 +1,23 @@
+/*
+ * Copyright 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 org.jmolecules.ddd.types
 
 /**
- * Identifies a value object. Domain concepts that are modeled as value objects have no conceptual identity or
- * lifecycle. Implementations should be immutable, operations on it are side-effect free.
+ * Identifies a value object. Domain concepts that are modeled as value objects have no conceptual identity or lifecycle.
+ * Implementations should be immutable, operations on it are side-effect free.
  *
  * Kotlin's counterpart of Java's [ValueObject](https://github.com/xmolecules/jmolecules/blob/main/jmolecules-ddd/src/main/java/org/jmolecules/ddd/types/ValueObject.java)
  *