A)
String str = "a string";
int length = str.length( ); // length == 8
http://download.oracle.com/javase/7/docs/api/java/lang/String.html#length%28%29
edit
If you want to count the number of a specific type of characters in a String, then a simple method is to iterate through the String checking each index against your test case.
int charCount = 0;
char temp;
for( int i = 0; i < str.length( ); i++ )
{
temp = str.charAt( i );
if( temp.TestCase )
charCount++;
}
where TestCase can be isLetter( ), isDigit( ), etc.
Or if you just want to count everything but spaces, then do a check in the if like temp != ' '
B)
String str = "a string";
char atPos0 = str.charAt( 0 ); // atPos0 == 'a'
http://download.oracle.com/javase/7/docs/api/java/lang/String.html#charAt%28int%29
To answer your questions in a easy way:
a) String.length();
b) String.charAt(/* String index */);
If you are counting letters, the above solution will fail for some unicode symbols. For example for these 5 characters sample.length() will return 6 instead of 5:
String sample = "\u760c\u0444\u03b3\u03b5\ud800\udf45"; // ???e
The codePointCount function was introduced in Java 1.5 and I understand gives better results for glyphs etc
sample.codePointCount(0, sample.length()) // returns 5
http://globalizer.wordpress.com/2007/01/16/utf-8-and-string-length-limitations/
1) To answer your question:
String s="Java";
System.out.println(s.length());
Source: Stackoverflow.com