What is the Difference Between `System.out.println` with a Char Array Plus a String and Just a Char Array in Java?

What is the difference between using `System.out.println(charArray + string)` and `System.out.println(charArray)` in Java?

In Java, the `System.out.println` method can handle different types of arguments, including primitives, objects, and arrays. When passing a char array along with a string, it behaves differently than passing just the char array. Understanding these differences is crucial for correct output formatting.

char[] charArray = {'H', 'e', 'l', 'l', 'o'};
String str = " World!";

System.out.println(charArray + str); // Output: Hello World!
System.out.println(charArray); // Output: [C@15db9742 (actual memory reference)

Causes

• When using `println`, a char array is treated as an object, resulting in its memory address being printed instead of the contents of the array.
• Concatenating a char array with a string causes the char array to be converted to a string, showing its actual character values.

Solutions

• To properly print the contents of a char array, you should use `System.out.println(String.valueOf(charArray));` which converts the char array directly to a string representation.
• When concatenating a char array with a string, ensure that the intent is to create a new string from the contents of the char array.

Mistake: Using `System.out.println(charArray)` expecting it to show the content of the char array.

Solution: Use `System.out.println(String.valueOf(charArray));` to print the actual characters.

Mistake: Assuming that `charArray + str` will print in the same format as `charArray` alone.

Solution: Understand that concatenation converts the char array to a string, whereas printing the char array directly does not.