Java | Get constructor reflectively
constructor, java, reflection
Solution
Your constructor is expecting an object array but you're passing a single `Long` to it.
Wrapping `latency` into an object array will work, although be careful as `newInstance()` itself is expecting `Object ...`, and if you pass it nothing but an `Object[]`, it will interpret it as a list of arguments. So you'll have to do something like this:
MyClass myInstance = ( MyClass ) clazzConstructor.newInstance ( (Object)new Object[] { latency } ) ;
or
MyClass myInstance = ( MyClass ) clazzConstructor.newInstance ( new Object[] { new Object[] { latency } } ) ;
The first one "fools" the compiler into wrapping your object array into another, the second one does it explicitly instead.
(Passing null only worked because null is null, no matter what the declared type of the parameter is.)
Problem
How I can get constructor reflectively, if its param is `Object ... objects`. My constructor: ``` public MyClass ( Object ... objects ) { if ( ! ( objects == null ) ) { if ( objects.length > 0 && objects [ 0 ] instanceof Long ) { setLatency ( ( Long ) objects [ 0 ] ) ; } } } ``` How I get it now: ``` Class< ? > clazz = Class.forName ( "MyClass" ) ; Constructor< ? > clazzConstructor = clazz.getConstructor ( Object [ ].class ) ; ``` What I try to do: ``` Long latency = 1000L ; MyClass myInstance = ( MyClass ) clazzConstructor.newInstance ( latency ) ; ``` And I get java.lang.IllegalArgumentException: argument type mismatch If latency == null, everything works.