package org.code2care.generics;
public class Example<T,V> {
public static void main(String[] args) {
System.out.println("Generics Example!");
}
public void method() {
T t = new T();
V v = new V();
}
}
Compilation Error:
Code2care@Mac % javac Example.java
Example.java:10: error: unexpected type
T t = new T();
^
required: class
found: type parameter T
where T is a type-variable:
T extends Object declared in class Example
Example.java:11: error: unexpected type
V v = new V();
^
required: class
found: type parameter V
where V is a type-variable:
V extends Object declared in class Example
2 errors
This is a violation of the rules of dealing with Generic types in Java. You cannot create an instance of generic type parameters.
Hence the compilation error clearly states that it was expecting a class type but a type parameter was provided.
![required class found type parameter error required class found type parameter error](https://code2care.org/java/generics-error-unexpected-type-required-class-found-parameter/images/ required class found type parameter error.jpg)
The ideal way would be to pass the type parameters as parameters to your method.
package org.code2care.generics;
public class Example<K,V> {
public static void main(String[] args) {
Example<String,Integer> example = new Example<>();
example.method("Sam",20);
}
public void method(K k, V v) {
System.out.println(k);
System.out.println(v);
}
}
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Author Info:
Rakesh (He/Him) has over 14+ years of experience in Web and Application development. He is the author of insightful How-To articles for Code2care.
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