How do generic methods solve the problem of type erasure?

Generic methods eliminate type erasure by embedding type information into the method signature, allowing the creation of polymorphic methods that are suitable for specific type situations: Generic methods are defined using type parameters. Use type parameters in methods just like actual types. For example, the max() method returns the largest object in a list of comparable objects. The getHighestPaidEmployee() method returns the employee with the highest salary from the list of employees.

Generic Methods Eliminating Type Erasure: A Coding Guide

Introduction

In Java, type erasure causes generic type information to be lost at compile time. Generic methods solve this problem, allowing polymorphic behavior to work in a type-specific context.

Generic methods

Generic methods use type parameters to define a common type in the method declaration. These parameters can be used in methods just like actual types.

For example, the following method receives a list of comparable objects and returns the largest object:

public static <T extends Comparable<T>> T max(List<T> list) {
  T max = list.get(0);
  for (T item : list) {
    if (item.compareTo(max) > 0) {
      max = item;
    }
  }
  return max;
}

Practical case

Consider a list of different types The element's employee list case. We need a way to get the highest paid employee:

public static <T extends Employee> T getHighestPaidEmployee(List<T> employees) {
  T highestPaid = employees.get(0);
  for (T employee : employees) {
    if (employee.getSalary() > highestPaid.getSalary()) {
      highestPaid = employee;
    }
  }
  return highestPaid;
}

Conclusion

Generic methods eliminate type erasure by embedding type information into the method signature. This allows us to create polymorphic methods that work in a specific type of situation without having to write a concrete implementation on each instance.

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