Why is the '==' operator not recommended for string comparison in some programming languages?

In Java, the '==' operator when comparing strings checks not the content of the strings, but the references — that is, whether both variables point to the same object in memory.

Therefore, to compare the contents of strings, it is recommended to use the .equals() method, which compares the sequence of characters.

Example:

String a = new String("test");
String b = new String("test");

System.out.println(a == b);       // false, different objects
System.out.println(a.equals(b));  // true, same content

Using '==' can lead to errors if the strings have the same content but are different objects.