Type Erasure

Java-Type Erasure

Type Erasure A generic type in Java is compiled to a single class file. There aren’t separate versions of the generic type for each formal parameterized type. For example, in the following example, Gen<Integer, String> and Gen<Float, Double> aren’t separate versions of the Gen type for each formal parameterized type : The implementation of generics utilizes type erasure. In … Read more…

Type Inference from Arguments

Java-Type Inference from Arguments

Type Inference from Arguments Generally generic method infer its type from its argument. For example , in the following generic method showAndGetV( ) calls look like normal method calls. But what if there is more than one argument? For example, following generic method showAndGetV( ) contain two arguments : All looks well when we give it … Read more…

Type Inference from Assignment Context

Java-Type Inference from Assignment Context

Type Inference from Assignment Context Generally generic method infer its type from its argument. For example, in the following generic method showAndGetV( ) calls look like normal method calls. But what if the type variable isn’t used in any of the arguments or the method has no arguments? Suppose the method only has a parametric … Read more…

Scope of Generic Method Type Parameters

Java-Scope of Generic Method Type Parameters

Scope of Generic Method Type Parameters Generic method can appear in either a generic or nongeneric class. For example, the following program declares a generic class called Gen and a generic method within that class called showUV( ). The showUV( ) method has its own parameter type declaration that defines the type variable U and … Read more…

Scope of Generic Method Type Parameters

Java-Generic Methods

Generic Methods It is possible to declare a generic method that uses one or more type parameters of its own. You can define generic methods in an ordinary or generic class. Methods within a generic type definition can also have independent type parameters. Generic methods are smarter and can figure out their parameter types from their usage … Read more…

Reading Type From Unbounded Wildcard

Java-Reading Type From Unbounded Wildcard

Reading Type From Unbounded Wildcard Unbounded wildcard<?> is really just a wildcard with a bound of type Object <? extends Object>. Obviously, even an unbounded wildcard instantiation holds objects that can be assigned to Object, so it’s OK to read an unbounded wildcard as the Object type : Our instantiation g1 returns type is Object. … Read more…