stringbuilder java extends object

The StringBuilder class in Java is a mutable sequence of characters. It is part of the java.lang package and extends the AbstractStringBuilder class, which in turn extends the Object class.

Here's the class hierarchy for the StringBuilder class:

Object
  AbstractStringBuilder
    StringBuilder

The StringBuilder class provides methods for constructing and modifying a string in a more efficient way than using the String class, which is immutable. It is often used when you need to perform multiple operations on a string and want to avoid creating multiple intermediate String objects.

Here's an example of how you can use the StringBuilder class to build a string:

StringBuilder sb = new StringBuilder();
sb.append("Hello");
sb.append(", ");
sb.append("world");
String s = sb.toString();  // s is "Hello, world"

You can find more information about the StringBuilder class and examples of how to use it in the Java documentation.