Java – I use generics, but not this class!

I tried to use Google collections to call this method to connect two arrays

public static <T> T[] concat(T[] first,T[] second,Class<T> type)

It returns an empty result I'm using it

ObjectArrays.concat(array1,array2,Blah.class)

This is the only thing compiled

Array1 and array2 are of type blah []

What is correct grammar?

Additional question: do other collection libraries contain documents with examples?

Editor: the problem is my bone code

public void register(ButtonPair[] pairs) {
    pairs = ObjectArrays.concat(this.pairs,pairs,ButtonPair.class);
}

The right side of things is good, but due to ambiguity, the left side is not assigned to this pairs. i 'm sorry! And hat Google collection!

Solution

The following are useful to me:

String[] arr1 = { "abc","def" };
String[] arr2 = { "ghi","jkl" };
String[] result = ObjectArrays.concat(arr1,arr2,String.class);

How do you get results from concat()?