Understanding Java Syntax for the '+' Operator

What is the syntax and usage of the '+' operator in Java?

int sum = 5 + 10; // Addition of integers
String result = "Hello, " + "World!"; // String concatenation

In Java, the '+' operator serves two distinct purposes: performing arithmetic addition and concatenating strings. This dual functionality can lead to a combination of numeric and string operations in one expression.

// Example of addition and string concatenation
int a = 5;
int b = 10;
int total = a + b; // total = 15

String greeting = "Hello, ";
String name = "Alice";
String message = greeting + name; // message = "Hello, Alice"

Causes

• The '+' operator is overloaded to work specifically for both integers (or numeric values) and String objects in Java.

Solutions

• To add two numbers, use the '+' operator directly between them, e.g., 'a + b'.
• For string concatenation, ensure at least one operand is a String. Java will convert other operands to string and concatenate them.

Mistake: Confusing between addition and string concatenation.

Solution: Ensure that one operand is a String when concatenating; otherwise, Java will perform addition.

Mistake: Using '+' in a context expecting only one type (e.g. only Numbers).

Solution: Always verify the types of both operands to avoid unexpected results.