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Primitive wrapper class in Java
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<p>In <a href="/facts/Object-oriented_programming/TxNMEcao">object-oriented programming</a>, a wrapper class is a <a href="/facts/Class_(computer_programming)/zvzkSAtE">class</a> that <a href="/facts/Encapsulation_(computer_programming)/kzDnbHPe">encapsulates</a> <a href="/facts/Data_type/fcx5hgVL">types</a>, so that those types can be used to create <a href="/facts/Object_(computer_science)/eX99dtAw">object</a> <a href="/facts/Instance_(computer_science)/5zPBGdX1">instances</a> and <a href="/facts/Method_(computer_programming)/8kAXxVYs">methods</a> in another class that needs those types. So a primitive wrapper class is a wrapper class that encapsulates, hides or <i>wraps</i> data types from the eight <a href="/facts/Primitive_data_type/0c898228">primitive data types</a>, so that these can be used to create instantiated objects with methods in another class or in other classes. The primitive wrapper classes are found in the <a href="/facts/Java_API/nRY3qexv">Java API</a>. </p><p>Primitive wrapper classes are used to create an <a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Object.html">Object</a> that needs to represent primitive types in <a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/util/Collection.html">Collection</a> classes (i.e., in the Java API), in the <a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/util/package-summary.html">java.util</a> package and in the <a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/reflect/package-summary.html">java.lang.reflect</a> <a href="/facts/Reflection_(computer_science)/Nj8stFfp">reflection</a> package. Collection classes are Java API-defined classes that can store objects in a manner similar to how data structures like arrays store primitive data types like int, double, long or char, etc., but arrays store primitive data types while collections actually store objects. </p><p>The primitive wrapper classes and their corresponding primitive types are: </p> <table><tbody><tr><th>Primitive type</th><th>Wrapper class</th><th>Constructor arguments</th></tr><tr><td>byte</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Byte.html">Byte</a></td><td>byte or String </td></tr><tr><td>short</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Short.html">Short</a></td><td>short or String</td></tr><tr><td>int</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Integer.html">Integer</a></td><td>int or String</td></tr><tr><td>long</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Long.html">Long</a></td><td>long or String</td></tr><tr><td>float</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Float.html">Float</a></td><td>float, double or String</td></tr><tr><td>double</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Double.html">Double</a></td><td>double or String</td></tr><tr><td>char</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Character.html">Character</a></td><td>char</td></tr><tr><td>boolean</td><td><a href="https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Boolean.html">Boolean</a></td><td>boolean or String</td></tr></tbody></table>