getMethods
- Java course
- Advanced
- Lesson 27/82
- 5 min
Learn method listing with getMethods.
Finding methods with getMethods
Class.getMethods() returns all public methods of a class, including inherited ones (for example from Object). Each method is a Method object.
Example: Method[] methods = String.class.getMethods(). In the returned array, m.getName() gives the method name, m.getReturnType() the return type, and m.getParameterTypes() the parameter types. To get only the class's own methods use getDeclaredMethods.
Inspecting a Method
A Method object carries plenty of information. getName returns the name, getReturnType the return type, getParameterTypes the parameter types.
Example: m.getName() and m.getParameterCount(). These methods let you discover a class's interface at runtime. A framework can learn which methods take which parameters and call them accordingly; this is a key tool in annotation processing and dependency injection.
Practice Find the length method of String
Find the length method with String.class.getMethod("length"). Print its name using getName() with System.out.println. Add throws NoSuchMethodException to main.
Starter code
import java.lang.reflect.Method;
// Find the length method with String.class.getMethod
// Get its name with getName
// Add throws NoSuchMethodException and printSample solution
public class StringMethods {
public static void main(String[] args) throws NoSuchMethodException {
Method m = String.class.getMethod("length");
System.out.println(m.getName());
}
}Expected output
length
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which method returns public methods, including inherited?
- getFields
- getConstructors
- getMethods Correct answer
- getClasses
Explanation: getMethods returns public methods.
2 Find a single method with getMethod
Method m = clazz.____("length");Method m = clazz.getMethod("length");Explanation: getMethod finds one method by name.
3 Match the Method methods
| Term | Meaning |
|---|---|
getMethods |
Public methods |
getName |
Method name |
getReturnType |
Return type |
getParameterTypes |
Parameter types |