Java is a widely used programming language known for its open-source nature, making it popular among developers. Strings are crucial in Java and are frequently used. They are backed by a character array, and the String pool stores them in a separate memory location. Strings are immutable, meaning they cannot be modified, and comparison is done using the "equals" method. Java supports operator overloading for string concatenation using the "+" operator. The "trim" method removes white spaces, and "substring" retrieves part of a string. Java programmers must have a good understanding of the String class to use it effectively.