Consider:
String s1 = "ABc";
String s2 = "abc";
System.out.println(s1.compareTo(s2));
On which basis the output will be -32 if only the first character decimal value of s1 and s2 are compared? Is this the correct way?
If String contains more than 1 character, then we should compare each character, but compareTo() method only compares the first character. Isn’t this a bug?
compareTo guarantees that it returns some negative number if s1 comes before s2 in lexicographic order.
When comparing "apple" and "banana", for example, you only need to look at the first character to determine that "apple" comes before "banana", because a comes before b.
interface Comparable, which String does implement. But, you could improve the answer by including a response to this part of the O/P's question: "On which basis the output will be -32".
String#compareTo method agrees, since the documentation does describe how non-zero results are calculated.
Awitha, suffices for knowing that a negative value must be returned. Which is all that the documentation promises us. Only if the first chars are the same (say,AandA), the method would need to look at the second char of each string.