Determines if the specified character is a letter.
<p>
A character is considered to be a letter if its general
category type, provided by {@code Character.getType(ch)},
is any of the following:
<ul>
<li> {@code UPPERCASE_LETTER}
<li> {@code LOWERCASE_LETTER}
<li> {@code TITLECASE_LETTER}
<li> {@code MODIFIER_LETTER}
<li> {@code OTHER_LETTER}
</ul>
Not all letters have case. Many characters are
letters but are neither uppercase nor lowercase nor titlecase.
<p><b>Note:</b> This method cannot handle <a
href="#supplementary"> supplementary characters</a>. To support
all Unicode characters, including supplementary characters, use
the {@link #isLetter(int)} method.
@param ch the character to be tested.
@return {@code true} if the character is a letter;
{@code false} otherwise.
@see Character#isDigit(char)
@see Character#isJavaIdentifierStart(char)
@see Character#isJavaLetter(char)
@see Character#isJavaLetterOrDigit(char)
@see Character#isLetterOrDigit(char)
@see Character#isLowerCase(char)
@see Character#isTitleCase(char)
@see Character#isUnicodeIdentifierStart(char)
@see Character#isUpperCase(char)
Determines if the specified character is a letter. <p> A character is considered to be a letter if its general category type, provided by {@code Character.getType(ch)}, is any of the following: <ul> <li> {@code UPPERCASE_LETTER} <li> {@code LOWERCASE_LETTER} <li> {@code TITLECASE_LETTER} <li> {@code MODIFIER_LETTER} <li> {@code OTHER_LETTER} </ul>
Not all letters have case. Many characters are letters but are neither uppercase nor lowercase nor titlecase.
<p><b>Note:</b> This method cannot handle <a href="#supplementary"> supplementary characters</a>. To support all Unicode characters, including supplementary characters, use the {@link #isLetter(int)} method.
@param ch the character to be tested. @return {@code true} if the character is a letter; {@code false} otherwise. @see Character#isDigit(char) @see Character#isJavaIdentifierStart(char) @see Character#isJavaLetter(char) @see Character#isJavaLetterOrDigit(char) @see Character#isLetterOrDigit(char) @see Character#isLowerCase(char) @see Character#isTitleCase(char) @see Character#isUnicodeIdentifierStart(char) @see Character#isUpperCase(char)