The Java toUpperCase() method is a built-in function in the String class that converts all characters in a String object to uppercase letters. The resulting String is a new String object, and the original String remains unchanged.
The syntax for using the toUpperCase() method is:
String str = "hello world";
String upperStr = str.toUpperCase();
In the example above, the original String str is "hello world". After calling the toUpperCase() method, a new String object upperStr is created with the value "HELLO WORLD".
It's important to note that the toUpperCase() method only works on ASCII characters, meaning that some special characters, such as those with diacritical marks or symbols from non-Latin alphabets, may not be converted correctly.
The toUpperCase() method is useful when you need to compare two String objects in a case-insensitive manner or when you want to present text in all uppercase for aesthetic or stylistic reasons.
