how to uppercase the first letter of a string in java

1String str = "java";
2str = str.substring(0, 1).toUpperCase() + str.substring(1);
3// str = "Java"

1String str = "java";
2String cap = str.substring(0, 1).toUpperCase() + str.substring(1);
3// cap = "Java"
4

1String str = "java";
2String cap = str.substring(0, 1).toUpperCase() + str.substring(1);
3// cap = "Java"

1String str = "hello world!";
2
3// capitalize first letter
4String output = str.substring(0, 1).toUpperCase() + str.substring(1);
5
6// print the string
7System.out.println(output);
8// Hello world!
9

1StringUtils.capitalize(..)

1class Main {
2  public static void main(String[] args) {
3
4    // create a string
5    String message = "everyone loves java";
6
7    // stores each characters to a char array
8    char[] charArray = message.toCharArray();
9    boolean foundSpace = true;
10
11    for(int i = 0; i < charArray.length; i++) {
12
13      // if the array element is a letter
14      if(Character.isLetter(charArray[i])) {
15
16        // check space is present before the letter
17        if(foundSpace) {
18
19          // change the letter into uppercase
20          charArray[i] = Character.toUpperCase(charArray[i]);
21          foundSpace = false;
22        }
23      }
24
25      else {
26        // if the new character is not character
27        foundSpace = true;
28      }
29    }
30
31    // convert the char array to the string
32    message = String.valueOf(charArray);
33    System.out.println("Message: " + message);
34  }
35}