java.lang.StringBuffer.appendCodePoint(int cp) is the method to append the string representation of the codePoint parameter to the sequence.

Syntax :

public StringBuffer appendCodePoint(int cp)

Parameters : 

In Java, the StringBuffer class is used to create mutable strings. It provides a number of methods that allow you to manipulate the contents of the string. One of these methods is appendCodePoint(), which is used to append a Unicode code point to the end of the string.

A code point is a unique number that represents a character in the Unicode character set. The appendCodePoint() method takes a single argument, which is the code point to be appended to the string. The code point can be any value from 0 to 0x10FFFF.

When the appendCodePoint() method is called, the string buffer automatically expands to accommodate the new character. The character is then added to the end of the string buffer.

Here is an example of how to use the appendCodePoint() method: 

StringBuffer sb = new StringBuffer();
sb.appendCodePoint(65);

In this example, the code point for the letter 'A' is passed as an argument to the appendCodePoint() method. The result is that the letter 'A' is appended to the end of the string buffer.

Overall, the appendCodePoint() method is a useful tool for working with Unicode characters in Java. It allows you to easily add new characters to a mutable string and manipulate its contents as needed.