Simple Generic Example

You can write a single generic method declaration that can be called with arguments of different types. Based on the types of the arguments passed to the generic method, the compiler handles each method call appropriately. Following are the rules to define Generic Methods −

  • All generic method declarations have a type parameter section delimited by angle brackets (< and >) that precedes the method's return type ( < T > in the next example).

  • Each type parameter section contains one or more type parameters separated by commas. A type parameter, also known as a type variable, is an identifier that specifies a generic type name.

  • The type parameters can be used to declare the return type and act as placeholders for the types of the arguments passed to the generic method, which are known as actual type arguments.

  • A generic method's body is declared like that of any other method. Note that type parameters can represent only reference types, not primitive types (like int, double and char).

Generic Method Example
package in.nareshit.raghu; public class Test { public void show(T input) { System.out.println(input); } public static void main(String[] args) { Test t1=new Test<>();"Hello"); Test t2=new Test<>();; } }

Generic Class along with Generic Methods
public class Box<T> { private T t; public void add(T t) { this.t = t; } public T get() { return t; } public static void main(String[] args) { Box<Integer> integerBox = new Box<Integer>(); Box<String> stringBox = new Box<String>(); integerBox.add(new Integer(10)); stringBox.add(new String("Hello World")); System.out.printf("Integer Value :%d\n\n", integerBox.get()); System.out.printf("String Value :%s\n", stringBox.get()); } }