Question

I’m writing a routine to invoke methods, found by a name and an array of parameter Class values

Matching the Method by getName works, but when trying to match the given Class[] for parameters, and Method.getParameterTypes(), I’m having trouble.

I assumed that this would work:

Class[] searchParams = new Class[] { float.class, String.class };
Class[] methodParams = m.getParameterTypes();


if(methodParams == searchParams) {
 m.invoke(this, paramValues);
}

But apparantly not - m.invoke is never reached. I've checked, and methodParams gives the same classes as searchParams.

The code below works, and picks the right method, but it seems like a very dirty way of doing things, I'm sure I'm missing something obvious.

Class[] searchParams = new Class[] { float.class, String.class };
Class[] methodParams = m.getParameterTypes();


boolean isMatch = true;
for(int i = 0; i < searchParams.length; i++) {
 if(!searchParams.getClass().equals(methodParams.getClass())) {
  isMatch = false;
 }
}

if(isMatch) {
 m.invoke(this, paramValues);
}

Answer 1

Arrays are objects, not primitives. Using == on objects only compares if they both points to the same reference, while you actually want to compare every individual array item separately.

You want to use Arrays#equals() for this.

if (Arrays.equals(methodParams, searchParams)) {
    // ...
}