Why am i get the error "object[] cannot be converted to Integer[]" in line 28.please when should one use int and integer?

Question

Method to reverse an array
https://code.sololearn.com/cvEuBk99uvss/?ref=app

Answer 1

. toArray() without parameter returns Object but you want Integer,
. with Integer[] array as parameter, stores result to this array with type Integer.

Integer[] lastval = new Integer[len];
List<Integer> list = Arrays.asList(chara);
...
lastval = list.toArray(lastval);

Answer 2

This should work:

//2nd methd
public static Integer[] reversArr(Integer[] chara){
int len=chara.length ;
List<Integer> list=Arrays.asList(chara);
Integer[] lastval = new Integer[list.size()];
Collections.reverse(list);
System .out.println(list);
lastval=list.toArray(lastval);
return lastval ;
}

* toArray returns an object array: Object[] (Object is the mother class of all classes)
* if you just write List list then the list uses Object as data type
-> use List<Integer>

More about converting list to array:
https://www.google.de/amp/s/www.geeksforgeeks.org/arraylist-array-conversion-java-toarray-methods/amp/

In your code you can just write int[] ...

int is a primitve data type. Integer is a wrapper class. It converts the primitve data type into an object.

https://www.google.de/amp/s/www.geeksforgeeks.org/wrapper-classes-java/amp/

I think you only need Integer if you want to use methods of this class.
int[] is an integer array. Arrays are always objects.