How to capitalize the first letter of a String in Java

by Taha Sıvacı · August 23, 2022

In Java, we can use substring(0, 1).toUpperCase() + str.substring(1) to make the first letter of a String as a capital letter (uppercase letter)

String str = "tahasivaci";

String str1 = str.substring(0, 1).toUpperCase(); // first letter = T

String str2 = str.substring(1); // after 1 letter = ahasivaci

String result = str.substring(0, 1).toUpperCase() + str.substring(1); // T + ahasivaci

A complete Java example to capitalize the first letter of a String, and a null and length checking.

package com.tahasivaci.string;

public class UppercaseFirstLetter {

public static void main(String[] args) {

System.out.println(capitalize("tahasivaci")); // Tahasivaci

System.out.println(capitalize("a")); // A

System.out.println(capitalize("@tahasivaci")); // @tahasivaci

//String capitalize = StringUtils.capitalize(str);

//System.out.println(capitalize);

}

// with some null and length checking

public static final String capitalize(String str) {

if (str == null || str.length() == 0) return str;

return str.substring(0, 1).toUpperCase() + str.substring(1);

}

Output

Tahasivaci

@tahasivaci

References

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