short and java.lang.ShortA primitive type:
.. /**
* Returns a {@code Short} instance representing the specified
* {@code short} value.
* If a new {@code Short} instance is not required, this method
* should generally be used in preference to the constructor
* {@link #Short(short)}, as this method is likely to yield
* significantly better space and time performance by caching
* frequently requested values.
*
* This method will always cache values in the range -128 to 127,
* inclusive, and may cache other values outside of this range.
*
* @param s a short value.
* @return a {@code Short} instance representing {@code s}.
* @since 1.5
*/
public static Short valueOf(short s) {
final int offset = 128;
int sAsInt = s;
if (sAsInt >= -128 && sAsInt <= 127) { // must cache
return ShortCache.cache[sAsInt + offset];
}
return new Short(s);
}
/**
* Parses the string argument as a signed decimal {@code
* short}. The characters in the string must all be decimal
* digits, except that the first character may be an ASCII minus
* sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a
* negative value or an ASCII plus sign {@code '+'}
* ({@code '\u005Cu002B'}) to indicate a positive value. The
* resulting {@code short} value is returned, exactly as if the
* argument and the radix 10 were given as arguments to the {@link
* #parseShort(java.lang.String, int)} method.
*
* @param s a {@code String} containing the {@code short}
* representation to be parsed
* @return the {@code short} value represented by the
* argument in decimal.
* @throws NumberFormatException If the string does not
* contain a parsable {@code short}.
*/
public static short parseShort(String s) throws NumberFormatException {
return parseShort(s, 10);
}
The central rule is:
\[\boxed {\text{Java may box a method argument, but it does not box a primitive receiver before } .}\]