In a + b + c, If variable a is a string : String class « Utility Classes « SCJP

1. SCJP
2. Utility Classes
3. String class

The Java compiler treats the previous code as if it were the following:

new StringBuffer().append(a).append(b).append(c).toString();

class MyClass {
  private int a;

  private int b;

  private int c;

  MyClass(int a, int b, int c) {
    this.a = a;
    this.b = b;
    this.c = c;
  }

  public String toString() {
    return "a = " + a + ", b = " + b + ", c = " + c;
  }
}

public class MainClass {
  public static void main(String[] argv) {
    MyClass t = new MyClass(11, 13, 48);
    System.out.println("Here it is: " + t);

  }
}

Here it is: a = 11, b = 13, c = 48