Java String concatenation with Other Data Types

Introduction

We can concatenate strings with other types of data.

For example, 

int age = 9;  
String s = "He is " + age + " years old.";  
System.out.println(s);

age is an int rather than another String.

The int value in age is automatically converted into its string representation.

Java will convert an operand to its string equivalent whenever the other operand of the + is an instance of String.

Consider the following: 

String s = "four: " + 2 + 2;  
System.out.println(s);

This fragment displays 

four: 22

rather than the 

four: 4

The concatenation of "four" with the string 2 happens first.

This result is then concatenated with the string equivalent of 2 again.

To complete the integer addition first, you must use parentheses, like this: 

String s = "four: " + (2 + 2);

Now s contains the string "four: 4".




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