Java Raw Types and Legacy Code

In this chapter you will learn:

1. How to use generic class in a non-generic way
2. Example - Java Raw Types

Deal with legacy code

To handle the transition to generics, Java allows a generic class to be used without any type arguments.

Example

Here is an example that shows a raw type in action:

class MyClass<T> {
  T ob;//from  w  ww  .  ja  v  a2s .c  om
  MyClass(T o) {
    ob = o;
  }
  T getob() {
    return ob;
  }
}
public class Main {
  public static void main(String args[]) {
    MyClass raw = new MyClass(new Double(98.6));
    double d = (Double) raw.getob();
    System.out.println("value: " + d);
  }
}

Output:

Next chapter...

What you will learn in the next chapter:

1. How to extend generic class
2. Example - Using a Generic Superclass
3. How to be a generic subclass
4. Run-Time Type Comparisons Within a Generic Hierarchy
5. How to override methods in a generic class

Java Raw Types and Legacy Code