Fix Generics: error unexpected type required: class found: type parameter

Code:

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.

Solution:

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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