From the course: Advanced Java Programming
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Using wildcards in generic programming - Java Tutorial
From the course: Advanced Java Programming
Using wildcards in generic programming
- Wildcards in Java can be useful in a variety of different situations. A wildcard is essentially an unknown type, and can give you more flexibility when writing methods. In this example, I have four classes. There is a class called building, a class called office, which extends building, a class called house, which also extends the building class, and finally a Main class. In the main class, I have a method called printBuildings. That takes a list of buildings as a parameter, and prints them to the terminal. In the main method, I also have a list of offices and a list of houses. However, I cannot pass either of these lists into the printBuilding methods. Because the list of type office is not a subtype of a list of type building. And nor is a list of type house. When I try and do this, I get a compile time error. One solution would be to create a new method for each different subtype of building. But a quicker and simpler solution is to use wildcards. In the list of arguments in the…
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