what i have tried is that first i took the integer input and checked that whether its is negative or not if its negative then again take the input
Scanner s=new Scanner(System.in);
int a=s.nextInt();
while(a<0)
{
System.out.println("please provide non negative integer input ");
a=s.nextInt();
}
System.out.println("the non negative integer input is "+a);
Here, you need to take the character input first and check whether user gave character or not if not than again take the character input
char ch = s.findInLine(".").charAt(0);
while(!Charcter.isLetter(ch))
{
System.out.println("please provide a character input ");
ch=s.findInLine(".").charAt(0);
}
System.out.println("the character input is "+ch);