Raw Type Troubles

Java-Raw Type Troubles

Raw Type Troubles A raw type is not type safe. Consider the following statements : The value of t1 inside rgen is obtained, and this value is cast to Integer. The trouble is that rgen contains a String, not an Integer. However, this cannot be detected at compile time because the type of rgen is … Read more…

Raw Types

Java-Raw Types

Raw Types Although the compiler treats different parameterizations of a generic type as different types (with different APIs) at compile time, but only one real type exists at runtime. For example, the class of Gen<Integer> and Gen<String> share the plain Java class Gen : Gen is called the raw type of the generic class. Every generic … Read more…

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…