Java data type conversion, what is the difference between parseXXX(String) or valueOf(String)?

Question

What is the difference between parseparseXXX(String) and valueOf(String) of the basic type of packaging class?

Answer 1

JDK8 source code

 /**
 * Returns an {@code Integer} object holding the value
 * extracted from the specified {@code String} when parsed
 * with the radix given by the second argument. The first argument
 * is interpreted as representing a signed integer in the radix
 * specified by the second argument, exactly as if the arguments
 * were given to the {@link #parseInt(java.lang.String, int)}
 * method. The result is an {@code Integer} object that
 * represents the integer value specified by the string.
 *
 * <p>In other words, this method returns an {@code Integer}
 * object equal to the value of:
 *
 * <blockquote>
 *  {@code new Integer(Integer.parseInt(s, radix))}
 * </blockquote>
 *
 * @param      s   the string to be parsed.
 * @param      radix the radix to be used in interpreting {@code s}
 * @return     an {@code Integer} object holding the value
 *             represented by the string argument in the specified
 *             radix.
 * @exception NumberFormatException if the {@code String}
 *            does not contain a parsable {@code int}.
 */
public static Integer valueOf(String s, int radix) throws NumberFormatException {
    return Integer.valueOf(parseInt(s,radix));
}

Using Inteager to illustrate here, valueOf actually calls parseInt.
The parseInt method is a static method of the Integer class. Its function is to convert a string into an integer. int
valueOf is also a static method of the Integer class. Its function is to convert a string into an Integer object.