OGNL has the following kinds of constants:

• String literals, as in Java (with the addition of single quotes): delimited by single or double-quotes, with the full set of character escapes.
• Character literals, also as in Java: delimited by single-quotes, also with the full set of escapes.
• Numeric literals, with a few more kinds than Java. In addition to Java's _int_s, _long_s, _float_s and _double_s, OGNL lets you specify _BigDecimal_s with a "b" or "B" suffix, and _BigInteger_s with an "h" or "H" suffix (think "huge" we chose "h" for BigIntegers because it does not interfere with hexadecimal digits).
• Boolean (true and false) literals.
• The null literal.