Method class in Reflection API
Introduction
- Method class in Java is part of the Reflection API and represents a single method of a class (either declared or inherited).
-
It is present in the
java.lang.reflectpackage. -
The
Methodclass allows you to get information about, and invoke, methods of a class dynamically at runtime. -
It provides methods to get metadata about a method, such as its name, return type, parameter types, modifiers, and also allows calling the method dynamically using
invoke(). -
Methodclass inherits theExecutableclass and implements theGenericDeclarationandMemberinterfaces.
Important Methods of Method Class
-
Below are some important methods of
Methodclass:- -
S.No Method Use 1 getName()Returns the name of the method. 2 getReturnType()Returns the return type of the method as a Classobject.3 getParameterTypes()Returns an array of Classobjects representing the parameter types.4 getModifiers()Returns the Java language modifiers (public, private, static, etc.) as an int. 5 invoke(Object obj, Object... args)Invokes the underlying method on the given object with specified arguments. 6 isVarArgs()Checks if the method accepts a variable number of arguments. -
Program:
import java.lang.reflect.*; class Calculator { public int add(int a, int b) { return a + b; } private void display(String msg) { System.out.println("Message: " + msg); } } public class MainApp { public static void main(String[] args) throws Exception { Calculator calc = new Calculator(); Class<?> c = Calculator.class; // Get declared methods for (Method method : c.getDeclaredMethods()) { System.out.println("\nMethod Name: " + method.getName()); System.out.println("Return Type: " + method.getReturnType().getSimpleName()); System.out.println("Modifiers: " + Modifier.toString(method.getModifiers())); // Print parameter types Class<?>[] params = method.getParameterTypes(); System.out.print("Parameter Types: "); for (Class<?> p : params) System.out.print(p.getSimpleName() + " "); System.out.println(); // Access private methods method.setAccessible(true); // Dynamically invoke methods if (method.getName().equals("add")) { Object result = method.invoke(calc, 10, 20); System.out.println("Invoked Result: " + result); } else if (method.getName().equals("display")) { method.invoke(calc, "Hello Reflection!"); } } } }Output:
Method Name: add Return Type: int Modifiers: public Parameter Types: int int Invoked Result: 30 Method Name: display Return Type: void Modifiers: private Parameter Types: String Message: Hello Reflection!
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