How to capitalize the first letter of a String in Java?

To capitalize the first letter of a string in Java, you can use the toUpperCase method of the java.lang.String class. Here's an example of how you can do this:

String s = "hello";

// Capitalize the first letter
String capitalized = s.substring(0, 1).toUpperCase() + s.substring(1);

System.out.println("Original string: " + s);
System.out.println("Capitalized string: " + capitalized);

This will output the following:

Original string: hello
Capitalized string: Hello

Alternatively, you can use the charAt and toUpperCase methods to capitalize the first letter like this:

String s = "hello";

// Capitalize the first letter
String capitalized = s.replaceFirst(String.valueOf(s.charAt(0)), String.valueOf(s.charAt(0)).toUpperCase());

System.out.println("Original string: " + s);
System.out.println("Capitalized string: " + capitalized);

I hope this helps! Let me know if you have any questions.