Java String isAlpha() Utility Method - Check String Contains Only Letters

This page contains the source code of the Java String isAlpha() utility method - This method checks if the CharSequence contains only Unicode letters.

This Utility method is very useful if you want to check if the given String contains only letters or not.

Java String isAlpha() Utility Method

The following String isAlpha() utility method checks if the CharSequence contains only Unicode letters:
/**
 * <p>
 * Checks if the CharSequence contains only Unicode letters.
 * </p>
 *
 * <p>
 * {@code null} will return {@code false}. An empty CharSequence
 * (length()=0) will return {@code false}.
 * </p>
 * 
 * @param cs
 *            the CharSequence to check, may be null
 * @return {@code true} if only contains letters, and is non-null
 * @since 3.0 Changed signature from isAlpha(String) to
 *        isAlpha(CharSequence)
 * @since 3.0 Changed "" to return false and not true
 */
public static boolean isAlpha(final CharSequence cs) {
    if (isEmpty(cs)) {
        return false;
    }
    final int sz = cs.length();
    for (int i = 0; i < sz; i++) {
        if (!Character.isLetter(cs.charAt(i))) {
            return false;
        }
    }
    return true;
}

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