I'm testing with Java reflection and trying to apply overloaded method to parameters according to their type..
However, I have NoSuchMethodException even though the method I tried to get is public. This exception still appears when I used getDeclaredMethod.
Here's the main program
public class Test {
public static void main(Object... inputs){
InputManipulation test = new InputManipulation();
for (Object input: inputs){
Class ownerClass = test.getClass();
Class inputClass = input.getClass();
Method method = ownerClass.getDeclaredMethod("add", inputClass);
method.invoke(test, "Testing reflection");
}
}
}
And here's the self-defined InputManipulation class
public class InputManipulation {
Integer total;
public InputManipulation(){this.total = 0;}
public void add(Integer num){this.total += num;}
public void add(String str){System.out.println(str);}
}
Thanks in advance!
I now changed the Test class as follows.. but the problem still exists.
public class Test {
public static void main(String[] args){
Test testExample = new Test();
testExample.testMethod("String1", 1, "String2");
}
public void testMethod(Object... inputs){
InputManipulation test = new InputManipulation();
for (Object input: inputs){
Class ownerClass = test.getClass();
Class inputClass = input.getClass();
Method method = ownerClass.getDeclaredMethod("add", inputClass);
method.invoke(test, "Testing reflection");
}
}
}
I also tried putting the inputClass into an array of Class, as suggested by another post, but it didn't help..
There seems to be a few issues with the initial code you provided and as others have suggested using an IDE would have pointed some of the issues out pretty quickly. However, I have taken your update and fixed the code to call the proper method in the loop you provided of input types.
First change your InputManipulation class like so:
public class InputManipulation {
Integer total;
public InputManipulation() {
this.total = 0;
}
public void add(Integer num) {
this.total += num;
System.out.println(this.total);
}
public void add(String str) {
System.out.println(str);
}
}
Now alter your Test class like so:
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class Test {
public static void main(String[] args) {
Test testExample = new Test();
testExample.testMethod("String1", 1, "String2");
}
public void testMethod(Object... inputs){
InputManipulation test = new InputManipulation();
for (Object input: inputs){
Class<? extends Object> ownerClass = test.getClass();
Class<? extends Object> inputClass = input.getClass();
//Method method; //not needed
try {
ownerClass.getDeclaredMethod("add", inputClass).invoke(test, input);
} catch (NoSuchMethodException | SecurityException |
IllegalAccessException | IllegalArgumentException |
InvocationTargetException e) {
e.printStackTrace();
}
}
}
}
I used these readings to help guide my answer, but altered the way I invoked the method: