Which statement lists the two common ways to concatenate strings in Java?

Which statement lists the two common ways to concatenate strings in Java?

• A. Using the - operator or the split() method
• B. Using the join() method exclusively
• C. Using the * operator or the append() method
• D. Using the + operator or the concat() method.

Answer: (D)

Two common ways to combine strings in Java are using the + operator and the concat() method. Strings are immutable in Java, so concatenation produces a new String object. The + operator is the most convenient and readable way to build strings, as in "Hello, " + name + "!" This reads like natural language, and the compiler typically turns such expressions into a sequence using a StringBuilder, which is efficient for assembling multiple parts. The concat() method offers a straightforward alternative: you call aString.concat(anotherString) to append the second string to the first and get a new String. It’s explicit and simple, but it only accepts another String as an argument, and it’s less flexible than using + when you’re combining different types or chaining many pieces. Other options don’t fit for basic concatenation: the - or * operators aren’t defined for strings, and split() divides a string into parts rather than joining them. There is a join() method for joining multiple strings with a delimiter, but it’s used when you need a separator between elements, not for simple two-piece concatenation.

Two common ways to combine strings in Java are using the + operator and the concat() method. Strings are immutable in Java, so concatenation produces a new String object. The + operator is the most convenient and readable way to build strings, as in "Hello, " + name + "!" This reads like natural language, and the compiler typically turns such expressions into a sequence using a StringBuilder, which is efficient for assembling multiple parts.

The concat() method offers a straightforward alternative: you call aString.concat(anotherString) to append the second string to the first and get a new String. It’s explicit and simple, but it only accepts another String as an argument, and it’s less flexible than using + when you’re combining different types or chaining many pieces.

Other options don’t fit for basic concatenation: the - or * operators aren’t defined for strings, and split() divides a string into parts rather than joining them. There is a join() method for joining multiple strings with a delimiter, but it’s used when you need a separator between elements, not for simple two-piece concatenation.