public static boolean validateIsBase64String(final String data) {

        if (data == null || data.length() % 4 != 0) {
            return false;
        }

        for (int m = 0; m < data.length(); m++) {
            final byte charByte = (byte) data.charAt(m);

            // pad char detected
            if (DECODE_64[charByte] == -2) {
                if (m < data.length() - 2) {
                    return false;
                }
                else if (m == data.length() - 2 && DECODE_64[(byte) data.charAt(m + 1)] != -2) {
                    return false;
                }
            }

            if (charByte < 0 || DECODE_64[charByte] == -1) {
                return false;
            }
        }

        return true;
    }
public static boolean validateIsBase64String(final String data) {

        if (data == null || data.length() % 4 != 0) {
            return false;
        }

        for (int m = 0; m < data.length(); m++) {
            final byte charByte = (byte) data.charAt(m);

            
            if (DECODE_64[charByte] == -2) {
                if (m < data.length() - 2) {
                    return false;
                }
                else if (m == data.length() - 2 && DECODE_64[(byte) data.charAt(m + 1)] != -2) {
                    return false;
                }
            }

            if (charByte < 0 || DECODE_64[charByte] == -1) {
                return false;
            }
        }

        return true;
    }
public static boolean validateIsBase64String ( final String data ) { if ( data == null || data . length ( ) % 4 != 0 ) { return false ; } for ( int m = 0 ; m < data . length ( ) ; m ++ ) { final byte charByte = ( byte ) data . charAt ( m ) ; // pad char detected if ( DECODE_64 [ charByte ] == - 2 ) { if ( m < data . length ( ) - 2 ) { return false ; } else if ( m == data . length ( ) - 2 && DECODE_64 [ ( byte ) data . charAt ( m + 1 ) ] != - 2 ) { return false ; } } if ( charByte < 0 || DECODE_64 [ charByte ] == - 1 ) { return false ; } } return true ; }
Determines whether the given string contains only Base64 characters.

@param data
the string, as a <code>String</code> object, to validate
@return <code>true</code> if <code>data</code> is a valid Base64 string, otherwise <code>false</code>
Determines whether the given string contains only Base64 characters .