{"id":5421,"date":"2023-09-23T11:52:28","date_gmt":"2023-09-23T10:52:28","guid":{"rendered":"https:\/\/www.baeldung.com\/java-value-based-classes"},"modified":"2023-09-23T11:52:28","modified_gmt":"2023-09-23T10:52:28","slug":"value-based-classes-in-java","status":"publish","type":"post","link":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/2023\/09\/23\/value-based-classes-in-java\/","title":{"rendered":"Value-Based Classes in Java"},"content":{"rendered":"

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1. Introduction<\/h2>\n
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In this tutorial, we’ll talk about a very interesting feature that Project Valhalla brings to the Java ecosystem, Value-based Classes. Value-based classes were introduced in Java 8 and have gone through major refactors and enhancements in later releases.<\/p>\n

2. Value-based Classes<\/h2>\n
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2.1. Project Valhalla<\/h3>\n
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Project Valhalla<\/a> is an experimental project by OpenJDK to add new features and capabilities to Java. The primary goal of this initiative is to add improved support for value types, generic specialization, and performance improvements while maintaining complete backward compatibility.<\/p>\n

Value-based classes are one of the features introduced by Project Valhalla to introduce primitive, immutable values to the Java language without the added overhead that traditional object-oriented classes bring.<\/p>\n

2.2. Primitives and Value-Types<\/h3>\n
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Before we come to the formal definition of value-based classes, let’s look at two important semantics in Java – primitives and value types.<\/p>\n

Primitive<\/a> data types, or primitives, in Java, are simple data types that represent a single value and are not objects. Java provides eight such primitive data types: byte<\/em>, short<\/em>, int<\/em>, long<\/em>, float<\/em>, double<\/em>, char,<\/em> and boolean<\/em>. While these are simple types, Java provides wrapper<\/a> classes for each of these for us to interact with them in an object-oriented way.<\/strong><\/p>\n

It is also important to remember that Java performs auto-boxing and unboxing automatically to convert between the object and primitive type efficiently:<\/p>\n

int primitive_a = 125;\r\nInteger obj_a = 125; \/\/ this is autoboxed\r\nAssert.assertSame(primitive_a, obj_a);<\/code><\/pre>\n
Primitive types live on the stack memory, while the objects that we use in our code live on the heap memory.<\/strong><\/p>\n
Project Valhalla introduced a new type in the Java ecosystem that is somewhat between an object and a primitive, and it is termed a value-type. Value types are immutable types, and they do not have any identity.<\/strong> These value types also do not support inheritance.<\/p>\n
Value types are not addressed by their reference but by their values, just like primitives.<\/p>\n
2.3. Value-Based Classes<\/h3>\n
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Value-based classes are classes that are designed to behave like and encapsulate value-type<\/em>s in Java. The JVM can freely switch between value types and its value-based class, much like auto-boxing and unboxing. Value-based classes are hence, identity free, for the same reason.<\/p>\n
3. Properties of Value-Based Classes<\/h2>\n
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Value-based classes are classes that represent simple immutable values. A Value-based class has several properties that can be categorized into some general themes.<\/p>\n
3.1. Immutability<\/h3>\n
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Value-based classes are meant to represent immutable data, similar to primitives like int,<\/em> and have the following characteristics:<\/p>\n