Integer+Integer in java 1.4

Question

``` Integer i1 = new Integer(10); Integer i2 = new Integer(20); Integer i3 = i1+i2; ``` Why in Java 1.7 this code works fine, but in java 1.4 I have error: ``` The operator + is undefined for the argument type(s) java.lang.Integer, java.lang.Integer ``` This is autoboxing issue or operator "+" is defined for Integer in java 1.7? How to proceed Integer+Integer in java 1.4 then?

Accepted Answer

Because autoboxing and unboxing is introduced from java 5 onwards. Java 1.4 can't understand that syntax.

How to proceed Integer+Integer

You need to get primitive `int` using intValue() and then do addition on primitive values.

Integer+Integer in java 1.4

Solution

Problem